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An automatic tester that doesn't get lost in a 'rat's nest'
VOL. 30 NO. 6 JUNE 1971

CHILTON'THE
ELECTRONIC ENGINEER

Memory course-bulk storage
What's new in connectors Two-way data system P"'.::...-~t... invades the home
Mini-sized PC socket offers repeat plug-ins and good contact

Leave my power supply system alone! You can get your own in only 9 days from Acopian.

"I tried struggling through that old built, tested and shipped it in nine

For immediate service, call the

power supply system catalog. It was days. Completely wired.

Acopian hotline: (215) 258-5441.

like a jigsaw puzzle, hunting for the

"So go order your own Acopian For literature, write Acopian Corp .,

pieces I needed for my new power system. There had to be a better way .
"Then I remembered the Acopian hotline. I called it. I told them the

power system .. . It's easy!"
HOW TO ORDER ACOPIAN POWER SYSTEMS

Easton, Pa . 18042. And remember, Acopian also offers 82 ,000 different DC power modules, every one

I

shipped with this tag . ..

DC voltages and currents I wanted. · Call Acopian collect

Discussed panel size. Meters . · Tell us the outputs and accesso-

Switches. And other accessories.

ries you need

"They gave me a firm price. Right on the phone. It was a lot less than I expected. I had our buyer phone in the P.O. And Acopian designed ,

· Get a firm price
· Shipment of completely wired system will be made in 9 days.

Circle Reader Service #1

Aluminum Electro/ tic Capacitors

THE

I

CRITIC'~

'LYTIC

)

Be critical. Specify Sprague Powerlytic®Capacitors for maximum capacitance in minimum space.

Type 390 Tubular Case

Type 360 Cylindrical Case

Case sizes from V2" x 1 Va" to 1" x 3 %". Operate at

Improved materials and processes now permit ex-

temperatures up to 85 C. Unique construction-anode

tended capacitance ratings. New, large case size,

and cathode terminals are welded-no riveted or

3 11

x

8

%11 ,

allows

capacitance

values

up

to

pressure connections-prevents open circuits, even in

650,000 µF. Ideal in applications such as computer

microvolt signal range. Standard ratings include ca-

power supplies, industrial controls, high gain amplifiers.

I

pacitance values to 18,000 µf, voltages from 3 to

Low equivalent series resistance, low leakage current,

450 VDC.

excellent shelf life.

Write for Engineering Bulletin 3415.

Write for Engineering Bulletin 3431 C.

Technical Literature Service, Sprague Electric Co. 233 Marshall Street, North Adams, Mass. 01247

Popular ratings are available for fast delivery from your Sprague Industrial Distributor.
THE BROAD-LINE PRODUCER OF ELECTRONIC PARTS

SPRAGUE®
THE MARK OF RELIABILITY

THE ELECTRONIC ENGINEER · June 1971

Circle Reader Service #2

l

~HEON
SEMICONDUCTOR. OUROPAMPS
HAVE PA METERS WITH TEETH.

Our new products are taking a chunk out of the operational amplifier market with parameters that are easy on desig ners and tough on competition . All of our de parameters are specified over the entire voltage range - with no fall-off .
The new RM4131 . It's unique in bipolar IC's, with input offset voltage of 2 mV maximum and 0.7 mV typical. Input offset current of 1O namp maximum and 2 namp typical. Th is high gain op amp has slew rates four times th at of 709's and 741 's. Typically 2 volts per microsecond with unity gain bandwidth of 4 MHz. And if low curren t drain at 20 V of 1.6 milliamps maximum is still not enough to put the RM4131 on your purchase order the large voltage signal gain should. It's typically 106 db from 3 to 20 volts.

Th e new RM4132 . It cuts power dissipatio n by two orders of magn itude and needs no external bias or compensation. This proprietary micropower op amp has typical current drain as low as 22 p.A. At maximum, 35 p.A. Input offset current is reduced to 0.7 namp. It maintains un ity gain bandwidth of 150 KHz. And it means further perfection in your battery operated circui ts.
Proprietary linear circuits is one of our great strengths. But it's not our only strength . We 're rapidly adding to ou r extensive line of off-the -shelf linear circuits as well. We provide the ti ghtest parameter specs you can get in monoli th ic op amps, differential and dual comparators, voltage regulators , line receivers , and sense amplifiers. All avai lable now at franchised Raytheon Semiconductor distributors.

Raytheon Semiconductor has changed. We have a new technical team. And new development programs providing new design tools. We ' re working on things like new digital analog interfacing that allow active switching and amplifying. Greater integration of external parts in vo ltage regulators. Greater circuit stability from improvements in temperature tracking. And we're going beyond the parame ters established for slew rates, offset voltage , noise, bias current and offset current.
If you haven't been keeping up with us lately you've got a surprise com ing. Write for our complete IC catalog and see. Raytheon Semiconductor, 350 Ellis Street, Mountain View, California 94040 . (415) 968-9211 .

CHOMP!

Circ/9 ReadBr S9rvice #3

THE

ELEGTR]\J G

I

EJ\GNEER

June 1971 Vol. 30 No. 6
Cover: Top left. The bu si ness end of Terad yne's N131 Co mputer-Operated Network Test System. described on p. 46 , is staring at you . Self-programming.
it simplifies network testing, no matter what the interconnection density. Bottom Right. Repeated plu g-ins for DIPs . LEDs, transistors. and so on .
are made po ssi ble with th es e new min ia ture PC soc kets-Be rg 's Minise rtTM . One of a number ot important co nnecturs discussed on p. 29 , thi s versatile socket co nsists of a specially designed , heat-treated spring within a tin -plated . d rawn copper square cup .

6 Editorial 10 Up to Date 16 Western Co lumn 18 Calendar 22 Speak Up 24 Microwor ld 29 Design Feature

41 Communicat ions 46 New Product Feature 49 Co urse 69 IC Id eas 75 New Pr od uct Fe ature 76 New Pr od ucts

82 Systems New Products 84 Lab New Products 86 Mic rowor ld New Products 89 Literat ure 94 Adverti si ng Index 96 Internationa l Corner

24 SPEED/POWER CHART FOR DIGITAL ICS By Lynda Rothstein
Pl otted for typical propagatio n delay in nanoseconds versus average power dissipation in m illiwatts pe r gate . here is the latest updated ve rsion of our annu al digital IC chart.

29 THEY'VE GOT CONNECTIONS By Smedley B. Ru th
Smaller, improved . and more versatile , the new generation of connectors are examined in thi s survey. Whether you 're wo rk ing with ICs or flat flexible cables or other components , the newest approaches in each category are discussed here.

41 CABLE COMMUNICATIONS: LOS GATOS EXPERIMENT By Sheldon Edelman
Data in the home? Some 1500 famil ies in Los Ga tos , Ca lif ., are participating in an experiment th at m ay have far-reac hin g soc iological and political implicat ions. in addition to wakin g up th e sleeping CT V ind ustry .

49 MEMORIES COURSE-PART 5
Where sheer m ass of mate ri al handled and cost are the two most important c on si derat io ns. th e answer is , of co urse, the bulk memory-the work horse of the memory syste m . From th e oldest paper cards , throu gh to the newest. opti ca l/ thermal , we cover all the bu lk memory tec hn iq ues . · Introduction By Steve Thompson · Punched paper cards By Dr. J. A. Carl son · Paper tape Contributed by Tally Corp . · Magnetic Tape By Edward S. Kinney · Optical/thermal mass memory By Harold Dell · Magnetic discs By Will iam Bertrando · Silicon drum By Dale A. Mrazek · Dynamic MOS RAMs By B. D. Broeker · Doma in wall memory By Berne D. Broadbent
69 IC IDEAS
· Zero crossing uses logic gates By Stuart Culo · Sinusoidal frequ ency halving By Mri rvi n K. Vander Koo i · Frequen cy divider from a clocked R-S flip-flop By Jozef Sabol · Speed up your precision rectifier By All en Co le

T HE ELECTRO NIC ENGI NEER · June 1971

3

THE HYBRID PRINCIPLE . .. FOR HIGH VOLTAGE
In the usual series-regulated power supp ly circuit, the series pass elements suffer th e maximum electrical stress. Their job is to abso rb a ll variation s, transients and noise so that these undesirables are filtered from the output. In the course o f this, the se rie s pass element often find s itse lf subject to excess currents, voltage and power dissipation, both tran sient and sustain ed.
When tran sistor s are used for the se ries pass eleme nt , the power suppl y designer build s into h.i s circuit eleme nts to keep th e o perating parameters within acceptable safe o perating regio ns. For in st ance, auxiliary fe edba ck is customarily supplied to limit current. Switching techniqu es may be used to limit dissipation and often transisto rs are se rie s con nected to share a hi gh. voltage stre ss.
For the control of high vo ltage (200 vo lts and up) , the prot e ction costs a nd complexity begi n to approach th e limit of practi ca lity .
To achieve lin ea r co ntrol of high voltage, Kep co ha s long-advocated the combination of va cuum tubes and transistors- even !C's- into a hybrid circuit where the grea ter to lera nce of tubes fo r high voltage recommend their advantageo us use as the se rie s pass element. Tubes, compared to high voltage tran sistors, are much more tol era nt of occasional overloads, will operat e safe ly with far fewer protecto rs and o perate without complaint at vo ltage levels that strain the reso urce s of a semicondu ctor junction.

TYPICAL HYBRID SIMPLI F IED SC HE MAT IC ABC (Hybrid) DE SI GN SHOWN
Th e re sult is an extremely reliab le, simple , high-vo ltage power supply using far fewer components than wou ld a fully tran sisto ri ze d versio n and consequently a more dependable design.
Th e Kepco hybrid prin cipal is fo und in the HB Series: 0- 525 vo lts up to 260 watts ; the BHK and OPS Series: autocrossover voltage/current regulato rs and o perationa l supplie s, 0- 500, 0 - 1000 and 0- 2000 volts, 200 watts and 20 watts , and the ABC (Hybrid) lin e: 0 - 200 vo lts to 0- 25 00 vo lts, 10 watts.

Write Dept. DM - 19
KEPCO, INC . · 131-38 SANFORD AVENUE· FLUSHING, N.Y. 11352
(2 12) 461-7000 ·TWX # 710-582-263 1

4

Circle Reader Service #4

THE ELEGTRJ\JIG
E/\DNEER
June 1971
Vol. 30 No. 6
K. Robert Brink ....... .................... . Publisher Alberto Socolovsky ............ ............ .. Editor John E. Hickey , Jr..... .......... .Managing Ed itor Smedley B. Ruth ..... .. .......... . Assoc iate Ed itor Sheldon Edel man .............Western Editors. F. Stephen A. Thompson ......Western Ed itor L.A. Arthur J. Boyle ..................... Technical Editor John McNichol .................... .. Assistant Edit9r Dr . 0 . M. Salat i ........................... Consultant Anne Axe ............ ................ Editorial Assistant Al ice C. Bach ...................... Editorial Assistan t Lynda Roths te in ........... .... . Editorial Assistant Debo r ah P. Wi lkins ............ Ed itorial Assistant Mae Moyer ....... ........... Editorial Reader Service Andrew Mittelbru nn ....... .Chilton Art Director Phaue Featherson ..... .. ........... .. ...... ..Artist George Baker ........ .........Washington News Bureau Neil Regeimba l........ .. .Wash ington News Bureau
Executive and Editorial Offices: One Decker Square. BaJa-Cynwyd . Pa 19004 Tel. (2 15) SH 8-2000
Address Mall to: 56th & Ch estnut Sts.. Philadelphia . Pa . 19139
Western Offices: Stephen A. Thom pson 3727 W. 6t h St . H202 . Los Angele s. Calif . 90005 Tel. (2 13) DU 7-127 1
Sheldon Z. Edelman 199 First St. Rm . 335 . Los Altos. Cali f. 94022 Tel (415 ) 94 1-6655
Chilton Officers & Directors: R. E. McKenna, President: J. Kofron, C. W. Hevner, Sr. Vice Presidents : W. A. Barbour, R. H. Groves, K. Rot>ert Brink , Publishing Vice Pres idents: James Miades, Trea surer: J. A. Montgomery, Jr.. Sec retary: T. J. Casper, S. H. Collmann, J. P. Kushnerick, R. 0. Nelson, E. C. Beaudet, W. A. Phair, D. Acton.
Monthly publicat ion of Chilton Company . Chestnut & 56th Sts.,
Phila.. Pa . 19139. (Area Code 215) SHerwood 8-2000. Controlled circulation postage paid at Philadelphia . Pa . $1 a copy . Subscription rates U . S. and U.S. Possessions: 1 yr. $1 2.00; 2 yrs . $20.00.
u.s: Canada 1 year $ 14.00; 2 yrs. $25 .00. All other countries 1 yr
$20.00: 2 yrs. p5.00. c Ch ilton Company 1971. Title Reg. Patent Office.. Reproduc_tion .or reprinting prohibited except by wntten authorization . Microfilm reproductions of The Electronic Engineer and its predecesso rs, Electronic lndu1trles and Tele· lech, may be obtained from Un iversity Mic rofilms . 313 N. First St.. Ann Arbor , Mich . The Chilton Electronics and Instrumentation Group The Elec tr onic Engineer Instruments and Control Systems Instrument & Apparatus News Medical El ectroni c News Electronic Components News
Chi I ton (!) Ej r::J:iM
THE ELECTRONIC ENGINEER · June 1971

Circuit breakers for MIL-SPEC equipment:

Two new military specifications have just expanded your design options. In fact, you may now be able to fill all your MIL-Spec breaker requirements from a single source. All of the breakers shown here are available in DC, 60-Hz, and 400-Hz models. All (with one exception) can be had in single- and multi-pole configurations. With a choice of time delays. Or in-

stantaneous trip. And the option of

built-in auxiliary switches. Worth in-

vestigating. Which we invite you to

do by writing us for any or all of the

product bulletins mentioned below.

Heinemann Electric Company, 2806

Brunswick Pike, Trenton, N. J. 08602.

Or Heinemann Electric (Europe)

GmbH , 4 Dusseldorf, Jagerhofstrasse

29, Germany.

5058

now you have a much greater choice.

MIL-C-55629. Series AM1: a new, lower-cost version of our popular AM12 breaker. Available in current ratings from 0.020 to 50 amp. Bulletin 3306. Series JA: compact, lightweight, with a good-looking white toggle handle as standard. Top current rating of 30 amp. Bulletin 3350.

19. Series HB:
rugged, sealed, explosion-
resistant, tested for operation under extreme
environmental conditions. Bulletins 3504 and 3505.

..
lighted-push
available in s· construction o
current rating of 30 amp. Bulletin 3351. MIL-C-5809. Series AM17: a
lightweight breaker engineered for airborne service. Available
In series-trip construction only; no auxiliary switch model. Current ratings from 0.100 to 50 amp. Bulletin 3305.

THE ELECTRONIC ENGINEER · June 1971

C irc/e Reader Service #5

5

EDIU<l/\L

When the potatoes are passed around
Last month. Representative Robert N. Giaimo (D.-Conn.) delivered the keynote speech before the Council of Engineers and Scientists (CESO) in San Diego. Mr. Giaimo's address expressed concern (he has sponsored legislation to aid science and technology) and contained a warning. This magazine both applauds and supports his concern-and believes his warning must be heeded . For this reason. we are excerpting here parts of Mr. Giaimo's address.
Alberto Socolovsky, Editor

Our failure to protect the scientific and technological commu-

nity is hurting this nation in many ways. For instance, ... the

annual public investment in each scientist and engineer in in-

dustry averages $50,000. Think what this means- the 65,000

scientists and engineers now unemployed represent the waste

of $3 .25 billion in public funds .

. . . Unfortunately, it is not hard to understand why the unemployment crisis in the scientific and technological com-

Representative Robert N. Giaimo

munity has been ignored for too long . How important are

65,000 jobless scientists and engineers, some people say, when

opportunities (to renew, update and extend your skills

compared to the total unemployment picture? How tragic is it

throughout your careers), you must take advantage of them.

that engineers must pump gas and physicists must drive tax-

When they do not, you must demand them . It is as simple as

icabs when millions of other Americans cannot find jobs at

that.

all? I submit . .. that this si tuation is both important and trag-

Second, the time has come for you and your colleagues to

ic (because) . . . for every highl y skilled scientist and engineer

realize (that) the days when you could sit back and wait for

put out of work, several unskilled workers will lose their jobs.

research money to come rolling in are over. The appropria-

The time has come for all Americans to realize the close rela-

tions process has many similarities to the dining room at a

tionship between unemployment in the laboratory and unem-

boardinghouse. When the potatoes are being passed around, if

ployment on the production line... . Yet you are treated by

you don ' t speak up yo u won ' t get any .

this nation as if yo u were merely products to be used and then

There has been a tendency among you and your colleagues

thrown away.

to act as if you were above politics, above government, above

Unfortunately, the Federal Government has never recog-

the battle for appropriations. Well, let me tell you something:

nized the fact that it has a special responsibility to protect our

you are not. If you want to start the money flowing agai n,

scientific resources because of its massive influence on (their)

you are going to have to climb down from the ivory tower,

deployment and utilization .

step into the arena, roll up your sleeves and fight for funds

. . . I have been heartened by the number of proposals in-

just like every other interest group in this country. As a mem-

troduced in this Congress to help you and your colleagues .

ber of the appropriations committee, I know what you are up

This shows, I believe, a growing awareness of your plight. .. . The legislation which I feel has the greatest chance of

against. The education lobby is fighting for funds. The poverty brokers are demanding more, the defense lobby, all of

success in this Congress is the Conversion Research and Education Act of 1971 , which Senator Edward Kennedy of Mas-

these and other groups are pleading with the federal govern-

sachusetts and I have introduced.* . . . I have several reasons for being optimistic about this

ment for more and more money . Just like in the boardinghouse, if you don't speak up, you won ' t get any .

legislation . .. I like (it) because it is good legislation , but I

Furthermore, the time has come for many of you ... to

like it even more because I think it can pass. . .. Congress (is trying to) solve this serious problem and
end, once and for all, the national disgrace of technical unem-

stop acting as though political actions were a dirty word. I (referred to) several bills now before Congress which deal with technical unemployment. Without (your vigorous support) these bills will not be worth the paper they are printed

,

ployment. Now I want to tell you what yo u must do. First of all, you cannot sit still. You are caught in a period

on. That . .. is political action. It is not a dirty word; it is a ne-

of change, and you must make every effort to adapt to the sit-

uation . When institution s both in and out of government offer

cessity under our form of government. You must become

more active in the Capitol, in the state houses, and at the

·This Act would establish three national policies:

First. scientists and engineers must have continuing oppor.tunitie_s for employment

in positions commensurate with their professional and technical skills.

.

Second . federal support and civilian research and development should be raised

to and maintained at the level of defense- related research and developme_nt.

Third . the total federal investment in science and technology should increase at

the same rate as the Gross National Product.

polls. You must support your representatives who are acting in your best interests and oppose those who are not. You must convince the American people a nd their government that your cause is just and your needs real. For if you do not help yourselves, who will?

6

THE ELECTRONIC ENGINEER · June 1971

with what we know a bout capacitors we could write
S~0~e did!

If you specify or buy capacitors you'll find the Aerovox Product Specifier for Electrical and Electronic Components the handiest thing that's come off the press since money. Between the covers we've included basic technical data, application data, Mil Spec an d industry data along with detailed product information on multi-layer ceramic, paper, film, mica, oil filled, high voltage, SCR, EDC, feedthru, disc and high voltage multiplier capacitors. In addition we have included technical information on our capabilities in thick and thin film microcircuits, RFl/EMI filters, and active and passive wave filters.
It's brand new, it's up-to-date and best of all ... it's FREE for the asking. So if you specify and buy capacitors, filters, or microcircuits, you'll want your own personal copy of this all important Aerovox catalog. Your copy is waiting for you; write for one today or call your local Aerovox representative.

~

·

t~\vh:< Aerovox·

AEROVOX CORPORATION, NEW BEDFORD, MASSACHUSETTS 02741 · TEL. 617·994·9661 PLANTS IN , NEW BEDFORD, MA., OLEAN & FRANKLINVILLE, N.Y., MYRTLE BEACH, S.C. AND HAMILTON, ONT., CANADA

THE ELECTRONIC ENGINEER · June 1971

Circ/e Reader Service #6

7

THE NICE THING A.BOUT OUR 54/74

MSI ·-="'~~./J
r

~ ~
Ii
I
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i
~
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I . I"'
i..
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I " ~
~ i!i
. ~ i
I
~
--
-CUSTOM

4183
MEMORY

j INTERFACE -

FAIRCHI TTL FAMI

From the Fairchild TTL Family Tree, our 54/ 74 series is another example of how we offer the freedom-loving designer the broadest range of products, packages, and speed/power rrade-off s.

TT Ls: YOU CAN GET THEM.

Currently available Fairchild 54/74 Devices

Hurting for 54/74's? You don't have to do business with delinquents. Instead, consider Fairchild. We will deliver the goods.

SSI Standard Gates 9N00/ 5400, 7400 9N09/ 5409, 7409 9N01/ 5401, 7401 9N10/5410, 7410 9N02/ 5402, 7402 9N11 /5411, 741 1

9N51 /5451, 7451 9N53/ 5453 , 7453 9N54 /5454, 7454

We're in the 54 / 74 business all the way.

9N03/ 5403, 7403 9N20/5420, 7420 9N60/5460, 7460 9N04/ 5404, 7404 9N30/ 5430, 7430 9N86/5486, 7486

To you, that means: 1. Our distributor and factory warehouses are fully stocked. You can get delivery on most circuits within a week. 2. We've always been big in ceramic packaging.

9N05/ 5404, 7405 9N40/ 5440, 7440 9N08/ 5408, 7408 9N50/ 5450, 7450
SSI Standard Binari es 9N70/ 5470, 7470 9N74/ 5474, 7474 9,N105/ 54105, 74105 9N72 /5472, 7472 9N76/ 5476, 7476 9N1 07 / 54107, 74107 9N73 /5473, 7473 9N104 / 54104, 74104
SSI High Speed Gates

Now all of our 14-pin SSI gates and flipflops are available in ceramic and plastic.

9H00/74HOOO 9H01 j74H01 9H04j74H04

9H05/74H05 9H10/7 4H10 9H20j74H20

9H22/74 H22 9H30/74 H30 9H40j74 H40

3. We have a broad line of 54/74 TTL devices

SSI High Speed Binaries

available now. Even more on the way. For you? Freedom of choice and packaging.

9H50/ 74 H50 9H51 /74H51 9H72J74H72

9H73/74 H73 9H74/74H74 9H76/ 74H76

9H78j74 H78

4. We offer package pricing flexibility in keeping with the breadth of line.

MSI Decoders / Demu ltiplexers 9315/ 5441, 7441 9354 / 5444, 7444 9358/ 5448, 7448 9352/ 5442, 7442 9357 A / 5446, 7446

Now a major supplier of second-source devices like the 54/74, we still continue our crusade for design freedom by constantly adding to our already vast

9353/5443, 7443 9357B/ 5447, 7447

MSI Registers 9391 / 5491 ' 7491 9394 / 5494 , 7494

9395/ 5495, 7495 9396/ 5496, 7496

family of proprietary TTL devices. The Big Tree.

MSI Latches

9375/ 5475, 7475 9377 / 5477, 7477

So if you're suffering from severe 54 / 74 deprivation, MSI Operators

get immediate relief. In the package you want.

9341 / 54181, 74181 9380/ 5480, 7480 9383/5483, 7483

From our factory or from any of our more than

9342/54182, 74182 9382/ 5482, 7482

MSI Counters

·

70 distributor locations throughout the country. And send for our new 54/74 D ata Sheet Catalog.

9360/74192 9390/7490 9393/7493 9366/74193 9392/7 492

F~IRCl-llLCJ SEMICONDUCTOR
FAIRCH ILD SEMICONDUCTOR. A Division of Fairchild Camera and Instrument Corporation, Mountain View, California 94040. (4 15) 962-50 11 . TWX : 910-379- 6435.
Circle R eader Service #7

UPD-CJ\TE

Mass memory bubbles
When Bell Labs first reported on mag-

identical particles which can do logic, memory and switching, without changing homogeneous structure. We have a

Cleaner air through electronics

netic bubbles, they were using orthoferrites . Next, they shifted to garnets as a medium for bubble devices. Garnets not only enabled Bell Labs to increase bubble density more than 100 to 1, but they were simple to use.
Bell Labs has successfu lly demonstrated circuits based on two deposition
methods . The epitaxial garnet has been deposited on non-magnetic substrates by both liquid-phase epitaxy and chemical vapor deposition.
Through these improvements in material technology, operation of a 10,404 step Y-bar shift register, with a storage density of 1 million b/in.' has been achieved with one such liquid-phase epitaxial film. With the realization of a bubble register of this capacity, Bell Labs has a fundamental building block for a bubble mass memory.

material-process system which promises adaptability and we are routinely making 1000-b shift registers at a density of 1.6 Mb/in .2· Just recently we operated a register having 10,000 b with good margi ns. We require < 0 .5 µW / B, corresponding to 6W for a 15- Mb bubble file."
Ending shocking experiences
We've all read and heard about patients in hospitals and in doctors' offices being killed by electrical shock . This problem has evoked a flurry of possible solutions for isolating the patient from this hazard.
Gilson Medica l Electronics In c ., Middleton, Wis., has devised a system

You may be breathing cleaner air, thanks to Figaro Engineering I nc.'s (Kobe, Japan) deoxidizing gas-sensing semiconductor marketed under the trademark TGS.
Composed of oxidized metals such as tin oxide a nd zinc oxide, the gas-sensing semiconductor decreases in electrical resistance when it encounters deoxidizing gases such as hydrogen, carbon monoxide, methane, propane, alcohol, volatile oil , and acetylene. Many times this resistance change is great enough for use without amplification.

they call lsolop which uses short range

telemetry to transmit test data from the

patient to receiver and display unit.

What makes this system unique, how-

ever, is the way it is powered .

Energy to operate the patient's transmitter co mes from solar cells. These solar cells use a light from the receiver to supply operating power. This eliminates the necessity for batteries which must be replaced and are a source of corrosion

A. Sensor B. Heater line for
the rma l com pensation C. El ect ro d e
D. Base

Mag nified magneti c bubbles (the light circ les) a re moving through a ci rc uit pattern formed on a thin epitaxial film of uni axial garnet. One bubble, somewhat elongated , can be seen in transition from one pole to the next in the center of the photo . The bubb les are 0.003 in . in diameter.

in medical equipment if allowed to decay over a period of time.
The s ketc h shows how the patient is isolated from electrical power with a telemetering syste m. The isolated transmitter derives its energy from a solar cell.

Over 40 patents have been applied for to cover this deoxidizing gas semiconductor detector , eight of whi c h have been awarded.
By combination with various electromechanical devices, TGS can be used as a detector or controller. The gas sensor

Bell Labs has also done experimental work on a "coi ncident block" mass

increases its conductivity as soon as it comes into contact with a gas and then

,.

memory organization which uses the

returns to its original resistance value

major-minor format. In this organiza-

when the gas has been removed.

tion , processed garnet chips with stor-

This semiconductor, unlike many oth-

age capacities of 20,000 bits a re inter-

ers, can withstand up to 50,000 hours of

connected to provide random access to

continuous exposure to steam with no

blocks of sequential data.

change in characteristics. There are po-

Of this technology, Jack A. Morton , vice president in charge of Electronics Technology at Bell Labs, said, " Mag-

Isoklted sender

tential applications for the device in enAC line vironmental pollution control as well as
its present use as a normal gas sensor.

netic bubbles constitute a technology of

Circle Reader Service #364

10

THE ELECTRONI C ENGINEER · June 1971

[ill]

~0<;),

Ts you a step ahead in design flexibility.
nitrode offers the only 1OOV PUT type and the only type with
uaranteed stability from - 55° C to +125°C. We also offered the
rst PUT in a hermetically sealed T0-18.
ith Unitrode's Programmable Unijunction Transistors (PUTs}, you're freed from the restricting fixed values of conventional UJTs. Simply by varying external resistor values, you can program Eta, Rse. fp and Ivto meet your particular needs in timing, pulse, sweep and
ensing circuits, oscillators and SCR triggers. The highest voltage, hermetic package and greatest temperature stability are three good reasons for specifying Unitrode PUTs. Three more are nano-amp leakage for long interval timing, low cost, and a strong applications engineering staff ready to help. PUT more design freedom at your fingertips ; order any of six types directly off the shelf.
For fast action, call Sales Engineering collect at (617) 926-0404 Unitrode Corporation, 580 Pleasant St., Watertown, Mass. 02172.

I - · U N IT R 0 D E quality takes the worry out of paying less.

r-----------------------------~
Unitrode Corporation, Inqu iry Processing Dept. 60 37 Newbury Street, Boston, Massachusetts 02116

Pl ease se nd free samples of PUT checked below (including data sheet).

Check
for Sample

Unitrode Type No .

Forward Voltage Rating Volts max.

Peak Po int Current µa max.

Valley
Point Check
Current fo r µa min. Sample

Unitr ode Type No.

Forward Voltage Ra ling Volts max.

Peak Po i nt
Current µ a max.

Valley Point Current µa min .

0

2N6 1 1 9 '

40

2.0@ 10V' 70@10V' 0

2N6138

100

0

2N6120>

40

0.15@10V 3 25@10V'

0

U13T3

100

D

2N6137

40

10 @ 10V' 40@10V 6 0

U13T4

100

1. Forme rl y U13T1 2. Formerly U13T2 3. Rc·HMl 4. RG · 10KO 5 . T·-SS"c , Rc·10K

10@10V' 40@10V' 2.0@10V' 70@10V' 0.15@10V' 25@10V' 6. T··125°C, RG·10K

NAME _ _ _ _ _ _ _ _ _ _ _ _ _ T I T L E - - - - - - - - - COMPANY _ _ _ _ __ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
~

ADDRE SS-----------------------~
CITY_ _ _ _ _ _ _ _ _ _ _STATE _ _ _ _ _ _ZIP:__ _ _ __

~-----------------------------~
Circ/e Resder Service #8

UPD-D\TE

The FCC makes its mind up? . . . Insiders close to the FCC's inner workings expect a decision within the next couple of months on the highly-charged data communications area. Such firms as MCI and Datran have petitioned the FCC to open up the rich data communications market to competition over the protests of the established common carriers like AT&T and Western Union .
IEEE leader appointed . . . Spotlighting medical care as one of the new priorities for electronics was the appointment of Donald G. Fink, general manager of the IEEE, to select advisory board on Redeploying Scientists and Engineers in the Health Care Field . This committee was recently created by the President's Advisory Council on Management Improvement, which is supported by the Bureau of the Budget's Office of Executive Management.
Unemployment survey ... To assess the extent of un- and under-employment among engineers, the National Science Foundation has contracted with the Engineers Joint Council to conduct a survey . The $65 ,000 survey will contact some 100,000 members of various engineering societies from a total of 450,000 engineers to find if they're working as engineers, and whether their employment is full-time or part-time.
Where to go ... As part of the administration's $42 million re-employment package, the Department of Labor has designated 14 areas for special job-finding assistance to engineers . To qualify, the professional must have been laid off from the aerospace or defense industries, have been employed in the industries for 12 of the last 24 months or permanently attached to it, and have been employed in one of the 14 areas. The areas are Huntsville, Ala. ; Los Angeles , Orange County, San Diego, and San Jose, Calif.; Cape Kenned y, Fla.; Atlanta, Ga.; Wichita, Kan .; Boston , Mass.; St. Louis, Mo. ; Long Island, N .Y.; Philadelphia, Pa .; Dallas and Fort Worth, Tex .; and Seattle, Wash . For specific addresses contact your local State Employment Office.
Job feedback .. . Results from the first two Philadelphia Workshops, co-sponsored by the American Institute of Aeronautics and Astronautics and the Federal Department of Labor, indicate that 49 % of the attendees were employed within two months of their participation in the program. According to C. C. Miesse, director of the AIAA Workshop, 30% continued in aerospace while 19% found "challenging positions in other fields ."
Seller beware . . . Tom Ingman, president of Powertec Inc ., blames not only poor business conditions and the availa bility of lower cost components, including 1cs, for forcing lower power supply prices. Another major factor is that the design engineer can buy a lot of circuitry for $30, only to find that a power supply to drive it will cost him more. The power supply being a major cost, he must shop for the best price instead of stringing along with "good old Brand X" simply because it's been reliable in the past.
12

Pill-less' therapy ... While still in the experimental stages, scientists and engineers are anxious about the prospect of using electronics to control heart rate, blood pressure, and even glandular secretions. Relying on a new technique, "bio-feedback training," and the fact that the involuntary nervous system can be voluntarily controlled, researchers use powerful amplifiers to let the patient see or hear the rhythms or conditions of his internal organs . With this feedback, patients have been able to successfully lower their heart rates and blood pressure by a type of mental concentration .
Industry standard for capacitors . . . The Electronic Industries Association is drafting an industry standard for metal cased paper and/or film dielectric SCR commutating capacitors to cover popular ratings, sizes, and measurements. Current range will be IO to 100 A rms, and ratings will include peak charging voltage and maximum operating frequency . Qualified persons are invited to contribute technical support to W. M. Robinson, Chairman, EIA Working Group p-2.2, Cornell-Dubilier Elect. , 1605 Rodney French Blvd., New Bedford, Mass .
Too much money . .. Backing his contention that $100k and up complex logic testers are unnecessary for testing 1c memories, President Bill Mow of Macrodata is selling the MD-100 memory exerciser (cost- $13 ,700) which functionally tests to 5 MHz. According to Mow, Macrodata consistently finds failure rates of manufacturer-passed packages higher than 20%. The low tester price should cut suer and manufacturer test costs by an order of magnitude and make 1¢/bit a more realistic target, says Mow.
Musing Ofer Munich's "Systems 71" ... Because the October 1970 Tokyo Computer exhibition was such a success for American participants (the U.S. Department of Commerce reported an immediate $2.5 million in sales) the U.S. Government has big plans for the November Munich Fair, "Systems 71. " The Fair will commemorate the quarter century anniversary of the invention of the computer. Since the Tokyo event occurred, a projected $54 million in first year sales has been generated and the Munich Fair is expected to do as well. There's room for 65 exhibitors, so if you'd like more information on this, contact Andre Williams at the Department of Commerce, (202) 967-2425 .
New manufacturing process . . . Signetics Corp. has announced a new manufacturing process for MOS 1cs. In addition, they predict that the process will be extremely useful in the manufacture of linear 1cs, high voltage discrete devices and small-signal microwave transistors. Dubbed oMOS, the process makes use of a double diffusion of channel and source impurities through the source opening in the oxide. This results in extremely short channel lengths (less than 1 micron) for higher speed operation but without the attendant voltage breakdown problems. Signetlcs predicts that it will be a year before they have the process in production, but they are currently making la boratory-type devices with it.
THE ELECTRONIC ENGINEER · June 1971

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free-for a 30-day evaluation. Check your DAC's performance and compare competitive prices. In that way you'll learn some eye-opening facts about the new Philbrick and its ever-growing capabilities. Then, 30 days after you've plugged our DI A or AID converter in your system we'll contact you . When we learn you like it, we'll apply the cost of your evaluation unit against your initial order- at the same discount price you earn through quantity purchases. If it doesn't perform to spec, return it. No questions asked ... no hassle. One outstanding thing you'll discover when you plug in a Philbrick DAC is that it was "human engineered." Pins and bits are in sequential orde r.

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THE ELECT RONI C t.N\.llNt.t.H · June 1971

Circle Reader Service #9

13

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Circle Reader service #10 14

UPD-D\TE

Standards gap . .. France, Britain, and West Germany have entered into an agreement to standardize their electronic components and establish a certification plan . Accordin g to Dr. Lewis M. Branscomb, director of the Department of Commerce's National Bureau of Standards, actions like this will further handicap U.S. electronic products, because "American industry is woefully underrepresented in the international standards machinery ."
Voice directs mail . .. Under the sponsorship of the U .S. Postal Service, RCA has developed an experimental device called the Numeric Speech Translator. Spoken ZIP code commands will be used to sort parcel past packages . This voice system requires no keypunching as does the present system in which one operator places an item on a conveyor belt while another must punch its ZIP code into a sorting machine .
Engineering employment conference . .. To answer such provocative questions as "What can be done about the thousands of unemployed engineers?" and "Can engineers cha nge gears? the National Society of Professional Engineers will sponsor a two-day fact-finding conference, June 17-18, in Wash ., D.C. For more information on "Engineering Employment- A Paradox," featuring among others Sen . Edward M . Kennedy , Dr. Myron Tribus (formerly with the Department of Commerce), and K. E. Kid-

doo (Lockheed personnel director) contact NSPE, 2029 K St., N.W ., Wash ., D.C. 20006 .
Bits of information .·· Teledyne Semiconductor is the new name fo r two consolidated Teledyne divisions: Amelco and Continental Device Corp.. .. A new engineering standard (RS- 378) developed by the Electronic Industries Association (EIA) for measuring the levels of oscillator radiation from fm and TV receivers was adopted by the Federal Communications Commission (FCC) . .. Communication in transportation is the subject of a seminar organi zed fo r June 14-17 by the EIA. Participants include officials from the Department of Transportation and the FCC.
A domestic communications satellite system proposed by Fairchild of Hiller Corp. can cut the costs of long distance telephone service to one-tenth of today's rates, the FCC was informed .' .. EIA reports color TV sales up 27.4% in March 1971 over the same month last year. All consumer electronic categories show increases in the first quarter of 1971 .
RCA has entered the glass business with the opening of a $19 million TV bulk and faceplate plant in Circleville, Ohio .. . The Mariner 8 and 9 spacecrafts will be controlled by Honeywell's guidance and stabilization systems. The two Mariners will explore Mars ... Bell Labs has developed a digital transmission system, the T2, to provide economical service over distances up to 500 miles . It should be available for commercial service in 1972.

Ask for your
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Circle Reader Service #31

Isolationist
Nobody likes line transients. Lab engineers hate them. Computer people get very upset when line transients flop their Flip-Flops. Now, you don't have to put up with that nonsense anymore. Our new little shielded "Isolationist" will give you high common mode rejection, stop high frequency line transients, put an end to 60 cycle leakage current and break AC ground loops ... simply and economically. 0.1to2KVA units (to 0.0005 pfd. coupling capacity) are available from stock to 2 weeks. Write for our catalog.
CEA .a division of Berkleonics, Inc.
1221 S. SHAMROCK AVENUE, MONROVIA, CALIFORNIA 91016 TELEPHONE : 12131 J5g.gz51
Circ/e Reader Service #11
15

Tired of smoking your RF generator?

Sierra's 470A high-power signal generator gives you automatic protection against no-load conditions.
Our 470A series give you stable RF power from 50 MHz to 1800 MHz. If you need 2400 MHz, ask us about that, too. The directreading power meter tells you your wattage (up to 50) at a glance. They can put out CW or a pulse-modulated signal. So they ' re perfect for development, test and service work on RF and microwave gear, for RFI susceptibility experiments and antenna pattern ranges. Get a Sierra 470A on your bench and you 'l l never smoke another generator.

The final oscil lator tube (the only tube ; everything
else is solid state) is so easy to replace you can
get back on the air in under a minute.

For additional information , write or call: Sierra Electronic Operation 3885 Bohannon Drive Menlo Park, Ca .94025 (415) 322-7222 TWX 910-373-1282
PHILCO~

Sierra manufactures a complete line of transmissi on, data and RF instruments for the communications industry.

16

Circ/e Reader Service #12

Untapped resources Former aerospace engineer Sam Suth
of the St. Regis Paper Co ., West Nyack, New York, presented an interesting paper at a recent co.nference on the use of digital computers in process control. His paper described an adaptive process control system in a paper mill. He prefaced his speech with a remark that only two years ago he had been in aerospace, with no knowledge of the paper business. However, since then he has found, through use of his aerospace experience, that saving 0.26 lb . of paper per ream adds $200,000 per year to profits.
Sam's work was roundly praised, although more than a dozen attendees prefaced their conversations with the remark , "I can't believe he came from aerospace!" Sam's success is no surprise to me. His failure would have been astonishing.
It was tragic to have heard some speakers say that they do not have the people available to implement systems they can economically justify. Others stated that, for any task, it is better to have one $20,000 per year man than two $10,000 per year men . And still others claimed that businesses need "systems programmers" to successfully choose computer systems or to buy from small manufacturers, while a great concentration of exactly that kind of talent is walking the streets today .
Men who have built and controlled the most complex systems ever can certainly contribute to automating processes . And yet there are many rationalizations for not hiring them : they are too highly paid ; they don 't understand our problems . They are paid well for a reason- they are good. If management flin.ches at the challenge of redirecting the efforts of men who have spent years solving "unsolved" problems, it is tired indeed .
These men are capable of understanding and responding to any corporate format or set of ground rules . Try one. Tell him your corporate facts of life; get him on board; and watch him go to work for you. Congratulations to the St. Regis Paper Co . for their insight into the fact that a good man is a good man, regardless of the company name on the building .
Western Editor
Circle Reader Service #13---.

Some think their working dayis arealchallenge. Somedon't
If you sat for eight hours sticking tiny little components into even tinier little holes, you might not be too excited about your job either.
But, even if people don't like the work, there are machines that do, the Dyna/Pert electronic component inserting machines from USM.
Dyna/Pert offers an entire line of component inserting equipment from small bench models, to semi-automatic units, to totally automated conveyor systems. Many of them can be either NC or computer control led. Dyna/Pert also has automatic sequencing systems and DIP inserters.
What's more, Dyna/Pert machines don't take coffee breaks, call in sick or look for new jobs. They just keep on producing at up-time rates in excess of 90%.
A Dyna/Pert machine wi II even pay for itself after a short period of time, and then start paying you. So don't you think it's time you woke up to Dyna/Pert? For further information contact your local USM office, or write USM Corporation, Dyna/Pert Dept., Machinery Division, 181 ElliottSt., Beverly, Mass.01915.
Visit the USM display at Booth 3600 during Nep/Con East.
USM Corporation
Machinery Division
The Productivity People

Circle Reader Service #14 18

O\LEND\R

JUNE

i7J 13 14 115 16

18 19

20 21 22 23 24 25 26

27 28 29 30

June 14-17: 47th Annual Convention of the Electronic Industries Association, Ar1i ngton Park Towers Hotel , Arlington Heights , Ill. Addtl. lnfo .-EIA, P. R. Dept. 2001 Eye St ., N.W .. Washington , D.C. 20006.
June 15-17: National Electronic Packaging and Production Conference (NEPCON '71 EAST) and the 1st East Coast SEMI· CONDUCTOR/IC PROCESSING & PRO· DUCTION CONFERENCE/EXHIBITION, New York Coliseum, New York , New York. Addtl. lnfo.-Don Peterson Industrial and Scientific Conference Management , Inc .. 222 West Adams St.. Chicago , Illinois 60606
June 15-18: Seminar on Thick Film Hybrid Technology, Unitek Corp., Monrovia, Cal if. Add ti. Info .-U n itek/ Weld matic Div., Seminars Coordinator, 1820 South Myrtle Ave .. Monrovia , Calif . 91016
June 17-18: "Engineering EmploymentA Paradox" Conference, Statler Hilton Hotel , Washington , D.C. Addtl. lnfo.-National Society of Professional Engineers, 2029 K St., N.W .. Washington D.C. 20006 .
June 22-25: Seminar on Monolithic I. C. Technology , Unitek Corporation , Monrovia , Calif . Addtl. lnfo .-Unitek/ Weld matic Div., Seminars Coordinator, 1820 South Myrtle Ave., Monrovia , Calif . 91016 .
June 27-30: 1971 Consumer Electronics Show, McCo rmi c k Pl ac e, Chi cago, Illinois . Addtl. lnfo.-Consumer Products Div ision , Electronics Industries Associ-· ation , 2001 Eye St ., N.W.. Was hingt on. D.C . 20006.
June 27-July 1: Design Automation Workshop, Shelburne Hotel, Atlantic City , N.J . Addtl. lnfo.-R. B. Hitchcock, Sr.. IBM, Box 218, Yorktown Heights, N.Y . 10598.

JULY

12 3

4 5 6 7 8 9 10

113 11 12

14 15 16 17

18 19 20 21 22 23 24

25 26 27 28 29 30 31

July 13-15: International Symposium on Electromagnetic Compatibility, Bellevue Stratford Hotel , Philadelphia , Pa . Addtl . lnfo .-Ralph Showers, Moore Sch. of EE, Univ . of Penna .. Philadelphia, Pa . 19104.
July 19-20: Summer Computer Simula· tion Conference, Boston Sheraton Hotel , Bo ston, Ma ss . Addtl . Info . - Mi c hael Mc Carthy, Wharton Sc h . of Finance, Un iv. of Penna.. Phil adelphia , Pa. 19104.

July 25-30: ISA's 1971 Research Conference on Instrumentation Science, Hobart and William Smith Colleges, Geneva , N.Y. Addt l. lnfo.-l nstrument Society of Amer ica, Education Services Dept., 400 Stanwix St ., Pittsburgh , Pa . 15222.
AUGUST
1234 56 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 271 28 29 30 31
Aug. 11-13: Joint Automatic Control Con· ference, Washington University , St. Louis. Mo . Addtl. lnfo.-R. W. Brockett . Pierce Hall , Harvard Univ ., Cambridge , Mass . 02138 .
Aug. 23-28: International Federation for Information Processing (IFIP) Conference, Ljubljana , Yugoslav ia. Addtl . lnfo.-U .S. Committee for IFIP Congress 71 , Box 4197, Grand Central Post Office , New York , N.Y. 10017.
Aug. 23-28: European Microwave Conference, Royal Inst. of Tech .. Stockholm , Sweden . Addtl. lnfo .-H . Steyskal, Eu ropean Microwave Conf., Fack 23 104 50 Stockholm 80, Sweden .
Aug. 24-27: Western Electronic Show and Convention (WESCON), Cow Palace , San Francisco, Calif . Addtl. lnfo .-Don Larson , WESCON , 3600 Wilshire Blvd ., Los Angeles, Calif. 90005 .
'71 and '72 Conference Highlights
WESCON-Western Electronic Show &Con· vention, Aug. 24-27; San Francisco. Calif .
NEC-National Electronics Conference, Oct. 18-20; Chicago, Ill.
NEREM-Northeast Electronics Research & Engineering Meeting, Nov . 3-5 ; Boston, Mass .
IEEE International Convention and Exposition will be called INTERCON '72. It will take place on March 20-23, at the New York Coliseum and New York Hilton .
Product noise and vibration reduction . . . This is only one of a number of training seminars being sponsored this year ·by B&K Instruments Inc. Scheduled for June 8 to 10, this seminar covers such topics as transducers , signal processing and data storage, real-time analysis, and computer interface . There's another one on industrial noise control scheduled for June 15-17 . We' ll be keeping you posted on future seminars to be held at the B&K Instruments facility in Cleveland, Ohio.
Circle Reader Service #271

The need : compact R/C networks in DIP's for terminator applications in new generation computer designs. To meet the circuit board space crunch , Allen-Bradley combines resistors and capacitors in a package compatible with automatic insertion equipment. These cermet networks save space and attachment costs. Packaged in dual in-line molded packs that lock out the environment and

match your IC's. Lead frames with built-in stand-offs are weldable or solderable. Volume production available.

SELECTED SPECIFICATIONS

TO LERAN CES

Absolute to ± .5 %

TRACKING

Excellent

RESISTANCE RANGE

10 o hm s to 10 megs, standard ; 1 ohm to 100 megs, special

CAPACITANCE RANGE

To 60 ,000 pF per cm '

TCR

As low as ± 100 ppm/°C

CA LIBRATION LEAD SPACING

Abrasive or laser 100 mil standard

Investigate the advantages of Allen-Bradley cermet R/ C networks. For information write: Marketing Department, Electronics Division, Allen-Bradley Co ., 1201 South Second Street, Milwaukee, Wisconsin 53204. Export office: 1293 Broad St., Bloomfield , N. J . 07003 U.S.A. In Canada: Allen-B rad ley Canada Ltd ., 135 Dundas Street, Galt, Ontario.

Circls R sader S srvice #15

ALLEN:BRADLEY @j)
Circle Reader Service #16 - -·

Engineering unemployment Sir:
The defeat of the SST symbolized the most significant commitment of Americans and our leaders towards the reorientation of our priorities. This reorientation includes budget cuts for NASA and defense research and development. It is safe to assume that this trend is substantial and of long duration.
As a former engineer I hold no special identification with the interests of the environmentalists or the aerospace and defense contractors. However from my recently acquired vantage point outside this economic upheaval I view the plight ol my former colleagues with empathy and sorrow. They are clearly the martyrs in this holy war waged by the ecologists and pacifists.
What I find particularly frustrating are the ad hoc and glib solutions offered to reemploy these engineers who are on the whole highly trained and educated.
Some say we should make them into teachers. But demographers tell us there

are and will be too many teachers . Also the salaries are much lower and the skills required for teaching do not fully tap the full capabilities of engineers.
Some say we should reemploy them in the peaceful application of engineering such as transportation, health services and urban reconstruction. To some extent this can be done but in many cases, perhaps most cases, the engineer trained in one specialization cannot be retrained in another. More important however is the fact that the jobs created for engineers will not equal those eliminated. Space and defense contracts had vast engineering inputs because the systems produced were few and complex. On the other hand the ecologist's application of engineers is largely on smaller projects produced many times. The televison for example has very little engineering in it when compared to a radar system. Well then where can engineers be employed quickly and efficiently so as to tap the full value of their ability?
I believe a program could be estab-

lished to train engineers to be management scientists within 6 to 12 months. This new field requires the application of analytical and mathematical concepts which are either familiar to or easily learned by most engineers . After this training program the government would assist them in obtaining positions as management consultants, technological forecasters, long range planners, operations research analysts, new product managers, business planners and a host of other positions created by the new awareness of corporate executives that quantifying the intangible is a profitable exercise. The important point is that the engineer is more than a specialist. He is a trained analytic mind . I would guess that of the 50,000 engineers who are presently unemployed at least I0,000 could be reabsorbed very effectively with such a program.
Jay Freeman New Products Manager
Ideal Corporation New York, N .Y.

MINI - MASS:~
ELIMINATES TRADE-OFFS OF SIZE, SPEED, OR ECONOMY!

This is the ultimate memory system for storing large blocks of random data. 12 1,4 " of panel height houses an entire 1, 179,648 bit memory system. The Mini -Massn· can be configured as a 32K x 36, 65K x 18, 131K x 9. Capacities start at 16K x 18 or 8K x 36 and can be expanded by simply inserting a single PC board for each 4K increment. Data save, byte control, power supply , systems enclosure, temperature tracking and wide range lithium core arrays are standard features . Field expan -

sion is ultra fast and ultra simple. Remember, the memory controller is built to address 65K words. By using two (2) controllers, the word length can be doubled to 36 bits with 32K words or you can operate as two separate 32K x 18 memory systems in the same enclosure. The entire I /0 wiring for 65K x 18 is contained on two (2) 86 pin connectors and four (4) 86 pin connectors for two (2) 32K x 18 or a 32K x 36 unit.

For all memory requirements, call or write today:

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22

Circle Reader Service #17

THE ELECTRONIC ENGINEER · June 1971

I

FAST RECOVERY, PLASTIC, AND AVALANCHE TYPES.

~

...-_- ~- ""'~"'·::::

Here they are : production quant1t1es of RCA's new fast -recovery silicon rectifiers, rugged plastic rectifiers, and hermetically-sealed control led avalanche rectifiers . Constructed to the highest standards of quality and reliabi lity, these and the many others in RCA 's established rectifier line are immediately available to fill your application needs.
Make use of RCA's 1- and 3-ampere diffused junction silicon rectifiers (D0 -26 and modified D0-4 packages) in high -speed inverters, choppers, and other high -frequency applications. Use RC A 's 1- and 1.5-ampere plastic rectifiers (D0 -15 package) in home entertainment equipment, industrial controls, appliance controls, and light industrial equipment. In instruments where reliable transistor protection is required , use RCA's hermetically -sealed (00-26) controlled avalanche rectifiers.
For more details, ca ll your local RCA Representative or your RCA Distributor , or write: RCA , Comm ercial Engi -
neering, Section 59F / UR10, Harri son, N .J. 07029 . lnterna tional: RCA, 2-4 rue du Lievre , 1227 Geneva , Switzer land , or P.O. Box 112, Hong Kong .

Rectifier
TA7892TA7895*
TA7898TA7901
TA7996, TA7802TA7806 *
1N53911 N5399
40808

Max .

Repetitive

Peak

Peak

Maximum

Surge··

Reverse Forward

Non·

Voltage Current

Repetitive

(VRRM l Avg. (lo) (RMS) IFSM

(V)

(A) (A) (A)

20 0-8 00

1.0 1.5 35

200-800

3.0 4.5 75

100-1,000 1.0

35

50-1,000 1.5

50

600

.5

35

Reverse Recovery Time (trr)
(µs) 0.5
0.5

Package
D0-26
modified D0-4 plastic D0 -15
plastic D0-15 D0-26

40809

800

.5

35

D0-26

*RCA Developmental types
**For one-half cycle of applied voltage (f = 60 Hz)
RCll

Solid State

Capability
fast recovery
fast recovery
general -purpose
general-purpose
controlled avalanche (700-11 00 V) controlled avalanche (900-1300 V)

T HE ELECTRO NIC ENGINEER · June 1971

Circle Read er S ervice #18

23

MICJO/\CRLD

Speed/power chart for digital ICs

Lynda Rothstein, Edit oria l Ass istant

Here it is fo lks- the updated version of your annual d igital

IC specifyi ng chart. We have plotted typical propagat ion

delay in nanoseconds agai nst the average power dissipation

(usually fo r a 50% duty cycle) in mill iwatts per gate. All of

the commercial 1cs listed are bipolar monolithic devices.

We have not included MOS and hybrids.

Each circuit configuration is indicated by a colored dot

on the chart, each color representing a di fferent type (as

shown in the key). The larger dots indicate the popul ar cir-

cuits made by several manufactu rers which have the same

or nearly the same speed /po wer characteristics .

This version of the chart is minus Ph ilco-Ford and Syl-

vania, for obvious reasons, shortening the listing somewhat

fr om las t year. Taking the elimin atio n of Ph ilco-Ford ~nd

Sylvania into consideration, the DTL and RTL devices have

remai ned much the same as last yea r, while there have

been a fe w addit ions to TTL, ECL and specials.

The list has been prepa red to help you pick out ind ivid-

ua l !CS shown on the chart. The number next to the manu-

facturer corresponds to the number of a circuit configuration sh ~ wn on the chart. For more information on

specific products, circle the num ber next to the ma nu fac-

turer and under the product type that interests you on the

Reader Service Number Cha rt.

~

For more infor mation, use these Reader Service numbers

Com pany

DTL RTL T-T-L -EC-L Specials

Ad vanced Mic ro Devices

201

Am elco

202 203 204

Am perex

205

206 207

Continental Dev ice

208

Fai rchild

209 210 211 212 213

Har ris

214

215

Hu ghes

216

217

ITT

218

219

Moto rola

220 221 222 223 224

Nati onal

225

226

RCA

227

228

Ra ytheon

229

230

SG S/Varadyne

231

232

Si e m e n s

233

234

Signet ics

235

236 237 238

Si licon ix

239

Sp rague

240

St ewart -Warner

241

242 243

Texas Inst ru m ent s

244 245 246 247

Transitron

248

BIPOLAR DIGITAL LOGIC CHART
DTL
1 Amperex FCJ 111 .201 2 Amperex FJC 121. 131 . 191. 211 3 Amperex FCJ 221 4 Amelco HNIL 300
Continenta l Device HNIL DTL 3308G , CG 5 Fairc hild LPDTL 9040
RCA CD2200 6 Amperex FJC 101 7 Amperex FC H 231 8 Amelco 6041 -6047 9 Amperex FCH 101. 121 , 141. 151. 181. 201 JO Texas Instruments MOD-DTL 53, 73 11 Amperex FC H 111. 131.161. 171.191. 211
Signetics SE/NEJOO 12 Fairchild DTµL 930
Hughes HSM 930 J ITT 9 30 RCA CD2300 Harris 930 hardened c irc uits Raytheon 930 Si liconix Sl830. 930 Stewart-Warner SW930 Texas Instruments 15930, 15830 13 Raytheon 200 series Signetics SP600A 14 National DTL DM930 15 Siliconix AO! , A41 16 Harris 200, 300, 500 17 Fairchild 9950 SGSNaradyne 9950 18 Silic onix SC 126/ 426 19 Motorola MDTL MC930/ 830, MCE930
RTL
1 Texas Instruments 17,900L, 17.SOOL 2 Fairc hild LPRTµL 9910 3 Motorola mW MRTL MC908, mW MRTL MCSOS/708,
mW MRTL MC808P/ 708P 4 Amelco JOO 5 Fairchild RTµL 900.9990 6 Motorola MRTL MC900/800, MRTL MC700,
MCSOOP/ 700P

TTL
1 Amelco 500-509 2 Amelco 530.548 3 Fairc hild 9LOO
4 National 54L Texas Instruments 54U74L
5 Amperex FJH 231. 25 1 6 Amperex FJJ Ill. 121. 191 7 Signetics NE/SE400J 8 Amelco 570.587 9 Signetics S/ N8400 JO Amperex FJJ 13 1 11 Amperex FJJ 101 12 Amperex FHJ JO!A, 1018 13 Amperex FHJ 121A, 1218 14 Amperex FJH 151. 161. 171 , 181. 221
Siemens FLH 100 series 15 Amperex FJH 101, 111. 121 , 131 . 241
Hughes HSM 5400/ 7400 ITT 5400/ 7400 Signetics S5400, N7400 Sprague 54174 Transitron 54/ 74 16 Amperex FJH 141 17 Amperex FJJ 181 18 Motorola Mttl I, MC500/ 400 Transitron TTL Series I Raytheon Ray I 19 Stewart-Warner SW 9601 20 Fairchild 9000 ITT 9000 20 Advanced Micro Devices 9600, 96LOO, 2600, 26LOO SGSNaradyne TlOO 21 Fairchild LP MSI 93LOO series Advanced Micro Devices 93LOO LP MSI 22 Amperex FHH lOlA, 101. 121A, 1218, 141A, 14 18, 161A, 1618, 181A, 1818 Motorola MTTL II MC2100/2000, MTTL 111 MC3 l 00/ 3000. MTTL MCE54H00/ 74HOO Harris 54HR (hardened TTL fam ily) Raytheon Ray 11 Signetics SH, 54H/ 74H Sprague 54H/74H Texas Instruments 54H/ 74H Tran sitron 54H/74H , Series II National 74H 23 Fairchild 9300 Advanced Mic r o Devices 9300 MSI.

93LOO LP MSI . 2501 SGSNaradyne Tl50 24 Raytheon Ray Ill 25 Texas Instruments 54/ 74 Signetics TTL SIN 8800 Fairc hild 54174 Nat iona l 54/ 74 DM 7000.8000 25 Amperex FJJ 211 (7 493). FJJ 251 (7 492) . FJJ 141 (7490) . FJL 101 (7441). FJ H 19 1 (7480) Stewart -Warner SW 5400/ 7400 series .Mot oro la MTTL MC8C5400, MC85400F, MC540017400 Advanced Micro Devices 54174 MSI . 8800 MSI Sprague US7500, US8500. USS/ US N9600 26 Ame lco 525-529 (TTL 1/ 4 mW gate. 1 µ sec prop. delay) 27 Texas Instruments 54S/ 74S 28 Signetics SIN 8200 Sprague USS/ USN8200
ECL
1 Mot orola MECL MC300/ 350 Stewart-Warner SW300, and 350 Series ECL I
2 Motorola MECL 10,000 RCA CD2·160
3 Signetics ECL II Motoro la MECL II MC1200/ 1000 Stewart-Warner SWlOOO. and 1200 Series ECL II
4 RCA CD2150 5 Fairchi ld 9500 Series temperature co mpensated
intermediate speed Texas Instrument s 2500 Amperex GH Family 6 Amperex FKH Ill , GU Family 7 Motorola MECL Ill , MC1660 8 Fairc hi ld 95HOO temperature co mpensa ted high speed 9 Amperex FS Family
SPECI ALS
I Motorola MHTL MC660 2 Signetics LU300K . SU300G/ K 3 Signetics LU and SP300A 4 Fairchild CTL I
c ::> ra1rc n110 IL 11
6 Siemens LSL (FZ H Series)

For a copy of this article, circle 249 on the Reader Service Car d.

24

T HE ELECTRO NI C ENGI NEER · June 1971

-i I
l"T'I

l"T'I
r

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0 z 0

150 130

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(;)

100

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90

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80

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70

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50

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FF??'? 2
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0.5mW 1.0

1.5

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6 28mW
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Power dissipation (mW/gate)

-41 4
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20

30

40 50 60 70 80 100 110

em ~gg{on
Everything about this
ffiOS/LSI packaging concept is economical. including our connector. And you can rely on that.

Our edgemount connector is specifically designed to help you take advantage of the economy and flexibility in leadless IC substrate packaging.
You get a// the substrate advantages: low initial cost, greater packaging density, easy insertion/extraction, quick replaceability. And the low per line cost of our connector matches the package's economy. Now, that's cost savings all the way.
Can you depend on it? Yes. Because our connector is designed to give reliable, uniform contact with every pad across the substrate. In addition, posts are rigidly
~Circle Reader Service # 19

molded in the block on .050" staggered centers, with no

exposed bent metal.

'

For specs and information on this connector and new substrate packaging concepts, write: AMP Incorporated, Industrial Division, Harrisburg, Pa. 17105

INCORPORATED
Manufacturi n g and Di r ect Sa l e s Facl/it l es i n : Aust r a li a , Ca nada, France, Great B r ita i n, Holland, Ita ly, Japa n, Mexico , Puerto Rico, Spa in, Swede n , Un it ed St a t es and Wes t Ger man y.

Circle Reader Service #20

27

-
.. :;: . ' <
.~.. - ·
',;1:

i}
,' <I
·~
·
·

CONNECTRONICS ···
a new packaging concept for solving interconnecting problems

From Elco. It's the Total Packaging Concept that helps you with your interconnecting design , then picks the right components for the job and puts them all together. To give you the best-performing total package back panel assembly at the lowest price.
No longer must you face a bewildering array of card cage, guide, panel, contact and input/output components, and evaluate specs vs . cost on the components that qualify. Nor must you establish quality control standards and inventory control on these parts. Nor make up a step-by-step production timetable. And watch the cost of your finished package mount because of unexpected labor costs. Or miss deadlines because of unforeseen design and manufacturing snags. Not when Elco's CONNECTRONICS specialists and N/C machinery can do the job. From concept to finished package.
All you do is furnish us with a drawing of the daughter card. Tell us how many cards you need . And give us voltage and ground requirements, cage mounting dimensions and a wire list. Then sit back.
We'll pick the right connectors from our hundreds of thousands of standard connector designs. And choose the right back panel. Perhaps it'll be our Variplate'" back panel, the interconnector that provides bussing and voltage and ground planes, accepts individual components in any configuration . And acts as a structural member as well.

Or, if the bacR: panel must be a mounting frame for p.c. board edge connectors or for rack and panel connectors, and must provide the rigidity that phenolic boards cannot, we'll furnish the Elco Variframe'" system. If your interconnecting configuration is standardized and your wiring changes are minimal, we'll use our Variboard '" interconnector . This system lets us do just about anything . Like mounting connectors or components directly on printed circuit boards. Or mounting connectors in plated -through or unplated holes. Mixing wired and printed circuits. And mounting boards on mother boards .

To complete the package, our special ists will select the compatible 1/0 section, then terminate the package. Automatically . .. N/ C . . . or a combination of both . Whichever is the most economical for you. Based on price/performance and delivery, you'll get the best interconnecting total package system avail able.
f rl/l For more information on CONNECTRONICS,~~ ··
the Elco Total Packaging Concept,write :

Elco, Willow Grove Division ,

--

Willow Grove, Pa. 19090 (215) 659 -7000

Elco, Huntingdon Division, Huntingdon , Pa . 16652 (215) 659 -7000

Elco, Pacific Division, 2200 Park Place, El Segundo, Calif . 90245 (213) 675-3311

Operati on s i n USA, Au stral ia, Be lgi um, Canada , Den m ark, Eng la nd, France, Ge rman y, Isra el an d Ja pan . Sales offices throu ghout the w orl d . Copyright © 1971 Elc o Co rp . Al I r ights rese rved.

28

Circle Reader Service #21

T HE ELECT RONI C ENGINEER · June 1971

They've got
CONNECTIONS
Spurred by the need for connectors and terminations to handle the popular IC packages, plus flexible cable and other components, the industry has developed new and different connectors
and connection concepts.

Smedley B. Ruth, Associate Editor
Normally, a connector new product announcement might read something like this- "The x-y-z company announces the addition of a 56-pin model to their line of rack and panel connectors," or "The a-b-c-company has announced the availability of a highly versatile connector on 0.100 in. spacing. It will take its place in the company's standard line of PC connectors," etc., etc., etc.
Although connectors of this type have been useful and will continue to hold an important place in the industry for some time to come, they cannot fully meet the needs of the industry today and of the near future . So, let's discuss some of those needs and see what the manufacturers are doing to meet them.
Smaller, improved and more versatile connectors and/ or termination methods are needed to handle the plethora of different IC packages ·(including components packaged in 1c-like DIPS) being used. One answer to this is the strip connector, several versions of which are now available. These are usually strips of insulators (housings) that contain contacts complete with tails. Some are fixed in length while others may be easily cut to any desired length. Some come in single strips, while others are sold in dual strips that may be cut apart. All have a singular advantageflexibility: they may be positioned on a board as needed and if your requirements change from, say a 14-pin DIP to a 16-pin unit, you merely cut your strips to suit. Handy , and it saves on inventory . But, before you abandon your conventional IC socket, be careful that the strips you buy meet your mechanical requirements and thaJ good engineering practices are applied in their design . For example, i_s the lead-in designed for easy IC insertion?
Another approach to the problem of how to reduce costs is about to be announced by Elco. Designed for back-panel
THE ELECTRONIC ENGINEER · June 1971

packaging systems, their Series 6317 Economist connector has individual solderless-wrap-type contacts that are pressfit into plated-thru holes on a PC board and an insulator that then snaps over the contacts. With this approach you can reduce the total package cost by using printed wiring for most of the circuitry and bussing. This greatly reduces the number of solderless wrap connections . In addition, if you would still like to be able to make circuit changes after the equipment is built, this concept lets you do it. Thus, you have the advantages of both solderless wrapping (versatility) and printed wiring (economy and reliability).
Since we're discussing so lderless wrapping, it seems an ap propriate time to mention another innovation soon to be announced . Although details of Ansley's new Signapoint termination system have not yet been released, I can tell you that it will compete with Gardner Denver's Wire Wrap and AM P's Termi-Point. It is a powdered metal ferrule that terminates component leads to posts, bus bars or other component leads by means of a pneumatic hand tool or semi-automatic machine . It will terminate wires 30 A WG or smaller (either solid or stranded) to miniature posts (of any configuration) to centers as small as 0. 100 in . And, it's a natural for terminating DIPS via the "d~ad bug" method . The "dead bug" approach
While we are on the " dead bug" (a DIP mounted upside down) approach, let's look at still another new method that was introduced at NEPCON 71 West. Berg's FlipDip TM mounting method is based on a simple procedure for staking posts onto a circuit board and using a special template to load and position DIPS during wave soldering . This method lets you visually inspect the connection, and eliminates the need for gold or silver plating of contacts and IC leads . With it, the IC packages are protected against
29

Low profile DIP strip receptacle recently introduced by AMP can be wave or dip soldered to PC boards . Retaining
detents on the contact posts allow the receptacles to be self-retaining when inserted into mounting holes. The strips are retained on a " breakaway ladder" which lets
you se parate them for use on any convenient spacing.

Signapoint termination system, soon to be introduced by Ansley, is actually a powdered metal component which term~nates component leads to posts , bus bars or other component leads.

Econom ist con nector from El co has contacts that are press-fit into pl a ted -thru holes on the PC board. The ins ulator is then snapped over the contacts . Damaged contacts are easily replaced without harming the adjace nt contacts or the insulator . Ground and voltage planes are also available .

heat-induced fai lures and the stress of insertion forces. Other fea tures are its low cost and the ability to mass mount or individually replace DIPS .
Anot her system that uses the inverted DIP method is Elfab's DIP-PAC. This design comes in standard sizes of 30, 60, 90, 120, 150, and 180 DIP positions on a board. The board provides an integrated ground and voltage plane on the wiring side connected to dummy pins or specified DIP locations, while the tail ·side is arranged for automatic wiring . Contacting fingers let you invert the DIP and plug it into the system.
Still another solderless method of mounting DIPS (and other com po nents) is SAE's DipStik system. Consisting of fou r basic parts, it lets you mount up to five (88 pins total) DIPS in three easy steps. It provides high capacitance, low impedance ground and power planes so necessary for ma ny of today's app lications. It also provides EMI shielding through the use of a metal cover that surrounds the solderless wrap pins and envelops the insulator body .
The impedance-crosstalk problem Since that old familiar word impedance was just men-
tio ned, let's look at it for a time . Actually, it's the problem of impedance matching that we should discuss, as more and more you must work with equipment that operates at hig her and higher frequencies, and with pulses having rise times measured in picoseconds . Thus, an impedance mismatch at a connector can cause serious problems. And crosstalk must also be controlled . It has been the practice
30

in the past to use standard coaxial connectors on the PC cards, but in the last year or two it has become increasingly evident that another solution must be found for use in high-speed systems. Contact and insulator designs must be improved to solve the problem . Texas Instruments and AMP have been pioneers in developing a solution. TI has a matched impedance edgeboard connector that can be used both as an impedance matching or a crosstalk control device and as a normal connector. Mechanically similar to standard edgeboard connectors, it is electrically almost equivalent to coaxial connectors.
AMP's contributions include connectors (with chevronshaped contacts) that combine the best features of both coaxial and PC board connectors . They are available in 50 and 75 fl families with vswRs as low as 1.06 at 5 GHz, crosstalk as low as - 80 dB and signal centerlines down to 0.050 in.
Zero insertion force connectors are also thought to offer a solution to some shielding and impedance matching problems. With this type of connector, the PC board or male member of the connector is placed in a female member which has one movable side. The movable side is then tightened or brought into contact with the male member by some method , such as screws or a cam locking device.
The zero insertion force concept is also useful in large memory planes and large testing connectors. And, it will probably solve a wear (on the substrate) problem in the new connectors for leadless substrates,
Remember that high density rack and panel connector
Continued on page 33
THE ELECTRONIC ENGINEER · June 1971

There are more reasons to buy Cannon

than other EDP connectors. One is DL.

ITT Cannon now offers you a full line of EDP
connectors. Printed circu it, input/output, flexible cable, microminiature-you'll find them all at Cannon. And some you won't find anywhere else. Like our exclusive DL's multiple-wire rectangular connectors with cam-actuated spring contacts. They feature low cost, low mating force and low contact wear. Their crimp and wire-wrapping terminations make them ideal for 1/0, cord-to-cord, and cord-to-panel applications.
Oth er input/ output connectors you 'll be interested in are our low cost Burgun-D subminiature rectangulars, and Cl 's (circulars combining low mating with high contact force) .
Some of the other reasons why Cannon means

EDP are: low-cost, versatile backplane assemblies ; bottom preloaded plate connectors ; MILC-21097 edgecard connectors ; lowcost circulars ; FLEX-LOC cable connectors; and microminiature rectangulars , circulars and strip configurations, including the 50MIL for memory core applications.
We've just shown you some of the reasons for connecting Cannon with all your EDP requirements. For others, contact ITT Cannon Electric, International Telephone and Telegraph Corporation, 666 East Dyer Road, Santa Ana, California 92702 (714) 557-4700.

Circle Reader Service #22

CANNON I TT

2048 Bit Kit

Introducing the MM6305, a 2048 bit field programmable ROM.
Last month we introduced a 1024 bit field programmable ROM. This month we outdid ourselves. The new 6305 uses the reliable fusible-link technology requiring only 90 mA for programming. Believe it or not, no special equipment is required, any test equipment can do it. Or, if you like, we'll sell you a portable programmer that you can throw in a suitcase and plug into any electrical outlet. Our new MM6305 is designed to be pin-for-pin compatible with our 1024 and 2048 mask programmable ROMs. That means you can be busy working on that prototype or preliminary design with one of our programmable ROMs while we're

booming ahead on your volume ROM requirements. That will cut weeks off your design cycle, dollars off your costs and get your boss off your back.
Think what you can do with this large bit capacity. Cut preliminary logic design to a few hours, utilize maximum flexibility in microprogramming techniques, develop and checkout higher accuracy look-up tables on the spot.
A few other good things about the MM6305 include an access time of 40 nsec, .25mW/bit power dissipation, and it's DTL/TTL compatible. It is organized 512 words by 4 bits with full address decoding included on the chip. Want to know the price? It's a low 5¢ a bit in small quantities - available NOW, in full mil temperature range (MM5305) and 0° to 70°C (MM6305).
MM6305 Highlights
40 nsec access time .2 mW/bit 512 words by 4 bits 16 pin DIP
m Programmed by ANY test equipment
Pick a winner, write, call, TWX or telex for full data. Do it quick!
Monolithic Memories
Monolithic M emories , Inc., 1165 East A rques Avenue, Sunnyvale, Ca 94086 (408) 739-3535 TWX : 910 -339-9229 Telex 346 301

32

Circle Reader Service #23

THE ELECTRONIC ENGINEER · June 1971

CONTACT LEAD FOR WIRE OR DISCRETE MOUNTING, & TEST PROBES

RECEPTACLE INSULATOR

HEAT SINK & DIP CLAMP RETAINER & COUPLING SCREW RETAINER
SHIELD

i

.520 WRAPPING LENGTH

- -1 DIPSTIK ~SSEMB:;

SHOWN FULLY ENGAGED

BUS BAR ASSEMBLY

DIP CLAMP & SPRING ASSEMBLY
DUAL INLINE PACKAGES

HEAT SINK & DIP CLAMP RETAINER & COUPLING SCREW RETAINER
SAE's Dip Stik system lets you mount , remove and replace dual in-lines-or change logic circ uitry-without using solder . You can mount up to five DIPs in three easy steps . Drop them into the cartridge , cla mp them in with the DIP clamp and spring assembly and then snap the load DipStik into the PC con nector-like receptacle .

CARTRIDGE IN SULATOR

you dreaded using because of the time and effort (and so metimes muscle) it took to mate and unmate it? Well, how about the new DL series connector from ITT Cannon? It has 156 cam-actuated contacts. As these contacts are not actuated until after they are mated, high engagement forces and contact wear are eliminated.
Flat cable connectors Flat flexible cable (FFC) is becoming increasingly popu-
lar and, understandably , more and more companies are developing connectors to be used with it. Being flat , these cables are easily stacked, conserving valuable space. But , unfortunately , most of the FFC connectors are relatively thick in the vertical dimension. This is one of the factors that dictates how many can be stacked in a given space. Thus, Ansley's newly introduced Flexstrip connector should be popular. Its three-piece construction includes contacts on a strip, a strain relief, and the connector shell. The contacts are on 0.100 in . centers (horizontally) and when the con nectors are stacked one on the other, the contacts are also on 0.100 in . centers in the vertical dimension.
One controversial point with all of these FFC connectors is the actual method of termination: soldering; brazing; welding (both through the insulation and to stripped conductors); various insulation piercing methods (by crimping, penetrating with knife-edge contacts, and so forth); or, by stripping the cond uctors and molding them to form the connector itself. All of these methods with their advantages and disadvantages have their advocates and opponents.
And now still another method from Berg is about to join
THE ELECTRONIC ENGINEER · June 1971

the growing list. It has the following features: termination directly to stripped conductors; dual contact points on each conductor; a built-in, easy-to-use strain relief; noncritical conductor-to-conductor tolerances of the flat cable; and easy termination with out expensive tools. There are four parts to the new assembly- a wedge and strain relief, a wire seat, the contact, and a contact housing . The wedge houses a stripped conductor in grooves on 0.050 in. centerto-center spacing. The plastic housing loosely holds the contacts and guides them into the grooves of the wedge.
Flatpack connector A lot of attention has been given to connectors for DIP
1cs, but what about flatpacks? Are there connectors to acco mmodate them? One such connector is the Becon carrier con nector introduced late last year by Teledyne Kinetics . Part of the Becon PC connector line, the flatpack model can mount seven IO-lead or five 14-lead flatpacks to PC boards of any thickness. With it you can change individual flatpacks without de-soldering or you can move the entire connector.
There is no need to solder or drill holes . The flatpack s are held in place by spring contacts, which snap in easily .
Are terminals connectors? In the electronics industry, it has been the practice to
use the term con nector to describe a multicontact unit as opposed to single conductor terminals or splices . Now, however, so many more designers are beginning to use female terminals (attached to the PC board by vario1,1s meth-
33

Cam-actuated contacts are featured in ITT Cannon's DL lnsta-Mate rack and panel connector. As the connector is mated . the center cam actuator shaft is unlocked , permitting engagement with almost no mating force . After engagement the shaft is rotated , sh ifting the hermaphrodite
co ntacts into a mated posi tion with high mating force.

Thes e carrier-connectors let you install flatpacks on PC boards without soldering or hole drilling. You ca n· mount and co nnect seven 10-lead or five 14-lead flatpacks (or a mixture of both) to PC boards with Teledyne Kinetics ' BECON co nnector. Gold-plated BeCu spring co ntacts snap in easily to exert 100-g force.

With Berg's flat flexible cable con nector, termination is made directly to stripped conductors. without expensive tools. You merely thread the exposed conductors through the wedge and strain relief. assemble the wire seat, and attach the wedge to the contact housing and secure .
ads) in place of female multi-pin connectors, that this definition isn't always a truly descriptive one. These terminals generally extend through the board so that their tails may be solderless wrapped or soldered, or whatever method you choose (with many of these terminals you may avoid soldering by press-fitting) . Ground bushings may sometimes be included when a reliable ground return is needed . These terminals, when used to mount DIPS or PC boards , might be thought of as female connectors sans housing . And this, of course, helps to cut costs because you aren't paying for a relatively expensive insulator.
Berg has made several contributions in this area- incl uding two part designs (a BeCu spring and a brass housing), and most recently the Minisert miniature PC socket (see cover photo), which provides repeated pluggability fo r DIPS, lamps, transistors, and so forth. This pluggable socket's design provides positive retention in the circuit board before soldering and spring-to-board electrical contact after soldering. The cup and spring extension is designed so that solder can be drawn to the top surface of a two-sided board, prod ucing a solder fillet on the top pad without overflow into the socket. The two-piece socket accepts both ro und or flat leads.
Although they don' t protrude through the board, AMP's new DIP and transistor receptacles also provide an economical and reliab le means for meeting the pluggability requirements of 1cs and transistors. Both come in strip form and can be installed by a high-speed automatic insertion machine, on a variety of grid patterns. The DIP leads accept flat leads and the transistor lead receptacles take round leads.
34

Minisert (also shown on the cover). another Berg product. has a heat-treated spring within a square c up soc ket . The spring is act ually soldered to the board to improve contact reliability. The tin-plated. drawn copper sq uare c up allows room for solder to wick up to the top pad .
An economy line of card edge connectors from the same company uses an insulator that is extruded, loaded with contacts and then cut. It's much cheaper to change the positions with an extruded insulator than it is with a molded part. And, they tell me that they also have a connector whose insulator is made of paper.
So wh at else is new! We understand that there is some pressure to improve
connector termination methods to use aluminum conductors. There has been much speculation in this area, but possibly it will soon be a reality.
Then there's the new brush contact from Bendix that has to be seen to be believed. The concept involves the mes hing of two wire brushes so that electrical contact is made between the sides of the wires . The many wires in contact with each other provide several parallel paths for current flow . The hermaphroditic contact design results in low electrical resistance.
Also from Bendix, long strictly a screw machine pin and socket user, is a new stamped and formed contact that meets performance requirements which were established for screw machine contacts.
Another approach to the current connection problem that looks promising is Cambion's Integrated Socket concept where you can take a handful of sockets and a frame and build only what you need . It reduces the number of connections needed and you can add to it as necessary. The socket is an 80-pin dual-in-line type. No PC is needed for support, as a means of mounting is molded into the ends of the socket.
THE ELECTRONIC ENGINEER · June 1971

AMP's economy line of card edge connectors uses an insulator that is extr uded , loaded with contacts and then cut. It's cheaper to change the positions with an extruded in-
s ulator than it is if you have a molded insulator. Two styles of snap-in card g uides are avai lable . Designed for dip or wave soldering. the contact posts are tin plated .

Ceramic substrate connector from Winchester provides a reliable means fo r connecting 1 x 2 ' in . pl ugga ble MSt!Ls1 c erami c circuit devices . A built-in guide ass ures proper sub-
s trate seating. Expect to s ee more of this type c onnec tor being introduced this year by various manufacturers .

Brush contact concept from Bendix involves the meshing of two wire brushes. Electrical contact is made between the s ides of the wires . The large number of wires in contact with each other provides parallel paths for c urrent flow . The conta ct design is , of course, hermaphroditic.

Although not new, use of the gold dot concept, s hown here on Sylvania's c ontacts , may well bec ome more popul a r th is
yea r. Use of the gold dots is s a id to extend co nt act life a nd to el imin a te poros ity problems whi c h m ay occ ur in gold pl ated c ontacts . And . it saves on the a mount of go ld used .

It's what's happening

Pat Moran of Bendi x; Bill Walkup of Cambion ; Stanley

The term pluggable has been used many times, perhaps

Hurst of Elco; Jerry Selvin of ITT Cannon; Joe Rose of

too many, but it's what 's happening . It seems that eve ry-

Scan be; a nd Waite Barre of Sylvania.

thing nowadays con tains pluggable items- autos, TV sets,

For more information concerni ng the co nnector prod-

washers, modular homes, co mputers, and on and on . And,

ucts manufactured by the following companies , circle the

pluggable items mean more co nnectors. Howeve r, the con-

appropriate reader service numbers. Also, see page 80.

nector manu fact urers are finding that price for these mar-

kets is cri tical; their customers want \4 or \/2 cent a line

connectors (gosh, remember those military contracts?). So

Company

how a re the co nnector com panies going to be ab le to meet these demands? Onl y one way they say- if the users will

AMP Amphen ol Ans ley

do away with th e ir hangups; th ei r prejudices .

AP In c.

They say that you must seriously consider using new plastic materials in place of metals in co nnector ap pli-

Bendix Berg Burndy

cations- it 's often possible . Devise new and more modern ways to meet new require ments, e.g. Have you seen the Diacon pack age? (The Electronic Engineer, Feb. 1971, p.

Ca mbi on Diac on El c o Elfa b

27 .) It is a new package that simplifies the overall ope ration of mounting complex 1c s . Constructed as a female

Gardner-Denver ITT Can no n Kin gs

'·

receptacle, it is mounted dir ect ly onto pins from PC boards, savi ng the cost of a socket. Don't automatically in-

Reli a ble S AE Sca nbe

sist on. precious metal or other high cost materials fo r co n-

Sylva nia

tacts . In sh ort, approach yo ur problem with an open mi nd .

Teledyne Kineti cs Texas In struments

Acknowledgements

Viking Win c hester

Reader Service No.
250 251 252 253 254 255 256 257 363 258 259 260 261 262 263 264 265 266 267 268 269 270

Many people supplied information for this report, but I

wo uld like to es peciall y thank Bob Harwood , Home r Henschen and R ichard O'Neill of AMP; Terry Leen, Henry

INFOR MATION RETRIEVAL

Pessah a nd Bennett Brachman of Amphenol ; D. J . C rim mins and Bill Sir.clair of Ansley; Bob Gabor of AP Inc .;

Connectors, Packaging

THE ELECT RONIC ENGINEER · June 1971

35

Memories are Better Than Ever ..
Yes, memories are better than ever - the MCM4064L MTTL 64Bit RAM proves it! Organized as a 16-word by 4-bit array, th e MCM4064L features an access time of less than 60 ns, all for 50% less than what you have been paying. Address decoding is incorporated on chip providing 1-of-16 decoding from four address lines. Separate Data In and Data Out lines, together with a Chip Enable, provide for easy expansion of Memory capacity. A Write Enable is provided to enable data presented at the Data In lines to be entered at the addressed storage cells. When writing, Data Out is the complement of Data In. Let's·take a look at a typical system using the MCM4064L as a main frame store of 128-words by 16-bits. Total devices involved are 32 MCM4064L RAMs, 9 MC7404P Hex Inverters, and 1 MC4006P 1-of-8 Decoder. To directly address the 128 words of memory would require seven address inputs. Since the MCM4064L has four address inputs, expansion is achieved by connecting the Chip Enable inputs of each device in a row, treating the system as an 8 row by 4 column array, and driving the 8 row lines with a 1-of-8 decoder (MC4006P). Address lines AO thru A3 are brought to all memory devices in the system via address drivers using a TTL fanout of 8. Each inverter/ driver represents four, one for each bit AO thru A3; thus sixteen inverters are required. The same scheme is used for the data input and output buffers. The four address bits AO thru A3 are common to each memory and are used to address the corresponding word in each MCM4064L. The output bit lines in each column are wire-ORed because the devices chosen by the Chip Enable signal are dominant. Lines Bl thru B4 in the leftmost column are brought out to four inverter/buffers as are the four data lines in the other three columns. Other organizations can be used but in wire-ORing MCM4064L outputs, eight was chosen as an optimum trade-off between decreasing decoding time versus increasing access time due to capacitance. The system provides a total access time of less 'than 100 ns typical and interestingly, a typical cycle time of less than 85ns. Data is written into the memory by selecting one memory device in· each row with the Chip Enable as was done for the read operation.
MTTL - Trademark of Motorola, Inc.

·· at NIOTOROLA

01301 4 D15D1s~----------------~

D9010 01101 2- - - - - - - - - - - - -
05 oa o1oa

11.u A\ 6'1 llo.3

r---t--t--..--'"-4'----,-4'--t----.--~w~'~~

E
* Each symbol represents fou r inverters. Each inverter is 1/6 MC7404. Note: R = 300 ohms.
128-WORO BY 16-B\T H\GH SPEED BUFFER MEMORY
This application demonstrates the versatility of the MCM4064L. Write for complete specifications to Motorola Semiconductor Products, Inc., P.O. Box 20912, Phoenix, Arizona 85036. We'll include another application describing a 512-word by 8-bit
memory. And to prove that speed isn't costly, the MCM4064L is now available at a 100-up price of $11.55. Evaluate now and you'll see that Memories are better than ever .. . at Motorola.
ltllOTOROLA ltllEltllORIES
IC Systems for the 70 'sf
C irc/e Reader S 8TVice #24

l '

. · . ·\
\ I .I

,,\ ,\t \

\

\

\

;;

'

Sooner or later, almost every computer company gets around to comparing itself to DIGITAL. And for good reason . DIGITAL has delivered over 10,000 small computers; more minis than all other computer companies combined.
Sure it's nice to be the manufacturer everyone tries to measure up to. But it's a responsibility too. Being the yardstick means always having the best. The best processors, the best peripherals, the best software. And we do.
But take a closer look at what it takes to be best. Like service. DIGITAL has over 1400 sales and service engineers in 65 locations around the world .

Or software and peripherals. DIGITAL offers more than 70 small computer peripherals - all the usuals, plus specials available only from us. And the most extensive software library and the most active users' society.
Cost performance? Our PDP-8/ e and 11 have the broadest cost/ performance range in the industry and we 'll prove it any way you like.
We could go on but you get the point. Sooner or later everyone has to measure up . To us.
Digital Equipment Corporation , Main .street, Maynard, Mass. 01754 (617) 897-5111 .

More than 10,000 mini-computers delivered. Circle Reader Service #42

From the same desig11 and manufacturing team who brought you the industry's most respected op amps and conve1ters.
Our new line is the best and most completefrom the low cost 432 (2% accuracy, slewing rate 45v/usec.) to the high performance 422 (3db bandwidth to 5MHz, slewing rate 120v/usec.) The 427 offers accuracy of 0.1% fu ll scale and offset drift of only 0.2mv/°C. Model 530 is the first complete IC multiplier, with 1% accuracy. And t here are others.
It can be confusing, especially if you know how many things multipliers can do besides computation.

Like rectification, phase-sensitive demodulation,

automatic level control, rms power measurement,

phase-locked loops.

So while we were building our multipliers, we

wrote a booklet- a 16-page guide to the theory and

applications of multipliers which is extremely help-

ful, surprisingly impartial, and free. It's called

"Evaluating, Selecting, & Using Multiplier

J I . Circuit Modules for Sig11al Manipulation & .
Function Generation," but just ask for

"the multipliers booklet." Analog Devices, ~

Inc., Norwood, Mass. 02062. (617) 329-4700.

o

r.ANALOG L.llllDEVICES

Where did all the inultipliers coIDe froin?

Circle Reader Service #25

COv1MLJN[LJ\fQV

CABLE COMMUNICATIONS:
the Los Gatos experiment
A little town in California is signaling the start of a new era in communications.

Sheld.on Edelman, IWest ern Editor- San Francisco
It looks as though the Federal Communications Commissio n wi ll reo pen the doo rs to expansio n of the cable-TV indu stry. In particular, the probable li fting of the top-IOOmarkets' rest ri ctio n, a nd the new requirement for local program orig in atio n have paved the way fo r new growth by sys tem operators, a nd thu s a lso by eq uipm ent suppliers as well .
Even non- CTV electro nics firms - firms which previously spurned th at industry as too crude to appreciate their capabilities- have caught the sweet scent of the dollar. (For in sta nce, $ 115 million for line equipment last year with a projected $600 million by 1980.) The CTV industry itself, somewha t dazzled by its own vision of the future, has begun to refer to itself, in a more general way, as a broadband cable-co mmunications industry- and rightly so.
The top- I00 markets' restriction of 1968 (together with certain oth er rulings) brought the cable-TV industry's growth to a halt. Cable systems were forbidden to import sig na ls into the top I00 market areas. These markets were defined by their percentage of television households, and thus represented the major metropolitan areas of the country. This freeze shows definite signs of a thaw.
The FCC has furt her ruled that by spring of this year, every CTV sys tem with more than 3500 subscribers must have faci lities for program origination. Now, this implies some type of two-way communications capability. The loca ll y ori gi nated material must be processed through the same equipment as that used to process, and start the distribution of, off-the-air signals. This head-end equipment is generally at the master receiving site, and this site is usually remotely located . But the local-origination studios must be convenient to the people who will use them . Thus , the sys tem must be able to ship the studio signal s upstream to the head-e nd for di stributi o n to the subsc ribers via the main , downstream trunk.
The ave rage cable system has less than 2000 subscribers right now , but this fig ure is expected to pass 6000 by 1980. Further, operating systems now total less than 2500, but are expected to be well in excess of 4000 by 1980. In fact, by that year almost 40% of the televisi on ho mes in this country will be se rved by cable. So it 's clear that the new rulings have vast implications for the growth of the cablecommunications industry.
THE ELECTRONIC ENGINEER · June 1971

Who needs two-way? You do . I d o. Our towns and cities do . The cable-TV
industry has long boasted of the services it co uld provide if given the chance to do so. Cable systems can change what is now a wasted appliance- a TV set- into an exciti ng piece of home electronic equipment.
And we ' re not talking just about 30 channels of off- theair and locally originated entertainment. Remember, the doors are now ope n: we're talking a bout electronic delivery of mail and newspapers, armchair shopping, fire and burglar alarms, automatic meter reading and billing, municipal and inter-school com munications, and so on.
But perhaps the most impo rtant cable-system service of all is the possibility o f getting a true and immediate response- fr o m a huge po rti o n of o ur population - to questi ons of na tional intere st via response terminals in eac h subsc riber's home. An individual will at least be able to have his opinion heard, even though he may not be able to "holler" as loudl y as the next man .
These services- which , by the way, are being pressed fo r by cit y co uncils across the na tion - need a two-way co mmunications ca pability, which can handle data communica ti o ns , m os t probably under co mputer co ntrol. Such services also need a quiet, relative ly inexpensive ($200-$300) hard-copy printer in eac h home* .
Two-way at Los Gatos Since its me rger with H & B American last September,
TelePrompTer has been th e largest system operator in the co untry. The co rporat io n chose Los Gatos fo r two- wa y transmission ex periments presumably beca use that system with its current 1500 subsc ribers (and hopes for anothe r 2000) and 27-c han nel capab ility is fairly typical of a modern plant (in o perati o n sin ce Dece mber, 1968).
At Los Gatos, Tele PrompTer is learning about the real problems associated with retrofitting or adapting an existing, o ne-w ay sys te m fo r two-way o peratio n- and such retrofitting will be co mm o n in the future. A nd though data tr ans mission has been at temp ted by a few other operato rs in the past, no one has tried it with a 1- Mb / s data rate as at Los Gatos.
*A pparen t \~ . ..;u ch a pr in1cr i!'> ddini lcl) on it" \\i.l). an.·ord ing. to Tele PrompTer spokes man at Los Gato.;, Cali f.
41

Now, the available downstream cable-spectrum spans 54 to about 300 MH z: 54 to 88 MHz for TV channels 2 through 6; 88 to 108 MH z for the fm band; nine midband channels between 120 and 174 MHz; and 174 to 216 MHz for TV channels 7 through 13 . The super-band channels ro und out the spectrum , sta rting at 2 16 MH z and running up to perhaps 300 MH z.
The upstream spectrum , for subscriber-originated communications , sits in the frequency range below 54 MHz. In the Los Gatos system , the upstrea m spectrum spans 5 to 35 MH z, which is about typical for an upstream allocation in a ny two-way cable system .
A system 's amplifiers a nd some of its passive components are unilateral, but the cable itself is, of course, bilateral. So it's possible to use crossover filters to steer the upstream signals around the downstream amplifiers, and vice versa . Such filters operate bilaterally and serve to separate a wide spectrum of signals into lo w and high frequency gro ups. Similarly , such fi lters co mbine, on a common output line, low frequency a nd high frequency inputs. And the Los Gatos system was retrofitted for two-way operation in this way , using Fairchild MOD upstream amplifiers a nd crossover filters; the downstream trunk uses Jerrold equipment. This type of retrofitting means that the system needs only o ne cable, which is much less expensive tha n havi ng separate cable and amplifier systems for the upstream and downstream signa ls.
Since the cable losses at the upstream freq uencies are much less than at the higher, downst ream frequencies , the system needs fewer upstream than downstream amplifiers. But every downstrea m amplifier location still needs a pair of crossover filters . The trick is to reduce to a minimum the number of filters needed, because they introduce phase problems.

Color TV and data errors

In theory, the full ba nd fr om about 5 to 54 MHz is

available for upstream work. But in practice, it is neces-

sary to introduce a guard band of 19 MHz between the

lowest downstream cha nnel (54 MHz) and the highest up-

stream channel (which is thus at about 35 MHz). This is

necessa ry in ord er to build , at a reasonable cost, crossover

filters with suitable phase a nd amplit ude characteristics.

The gain-phase characteristic of such filters dictates

their gro up-delay performance . If the filter's group delay

varies with frequency , it causes group-delay distortion .

And in the tra nsm ission of a color-TV signal , group-delay

d.istortion causes a time differential to appear between the

luminance signal a nd the chrom ina nce signal that is 3.58-

M Hz higher in frequ ency .

When this time delay is long enough- about 200 ns-

yo u see on yo ur TV screen the "funny-paper" effect: a mis-

registration between the brightness (luminance) and color

(chrom inance) information. And this same phenomenon-

gro up-delay distortion- ca uses distortion in data trans-

mission . The time delays caused by the crossover filters

are additi ve, thus the need to reduce the number of filters

needed.

Continued on page 44

42

r-T-;;;-nk - D i;;;;t~ol - - - - - ,

1 amplifier

co upler

Downstream

I

Trunk 1

I Trunk

(in) >-I-_ _, '>----~+--------, (out)

I

Distribution

I

I

(bridger)

I

:

ampl i fier

I

I

4-woy

I

spl itter

I

I

L------------- .J

Distribution line s (out)

One-way street. The backbone of any cable TV system is a downstream trunk line that carries programming from the head -end receiving site for distribution to subscribers ' homes. Tr unk am plifiers are spaced at 1300- to 1800-ft intervals . This illustration shows a bridging station , which houses a distribut ion (" bridging") am plifier in addition to the trunk amplifier. Such a station provides several feeder lines . And subscribers ' taps attached to such feeder lines will not disturb the main trunk line.

Tru nk

-5- 35 MHz
Upstream

L

L

· ~ I Upstream

I

I

I

L _ _ _ - I _J !:!£s~a ~ _ _ _ _ _ _

Dis tri bu tion lines

One cable, two directions. Frequency-division multiplexing
via filters allows both upstream and downstream signals on a si ngle cable. The crossover filters have a low-pass corner at 35 MHz, an d a high-pass corne r at 54 MHz. Here , the upstream and downstream paths and components are shown in different colors ; the downstream portion is the same as shown in the bridging-station illustration for a one-way sys tem . In the Los Gatos system , the components needed to retrofit for two-way operation are add-ons, external (exc ept for one filter) to the downstream station equipment. (At Los Gatos , the upstream amplifiers are Fai rchild MOD AR-20's, and the crossover filters are Type FD-l 's . The downstream equipment is manufactured by Jerrold.) But the unitized const ru ctio n sh own here has the advantage that the manufacturer 's design staff has total control of package perform ance, and probably will be commonly used in future retrofits .

For more information on Fairchild MOD AR-20's and Type

' D-l 's ,

Circle Reader Service #272

For more information on the Jerrold product line,

Circle Reader Service #273

THE ELECTRONIC ENGINEER · June 1971

Production people. Lab special ists. Q.C. techn ic ians. Circuit designers. And researchers. There's a Krohn-Hite Function Generator to meet all their needs. Dependably. Accurately. Economically. Prices start at $295 and end at $550. Featuring solid versatility and down-to-earth performance.

Models cover the frequency range of 0.002 HZ to 5 MHz. Wavemaking capability for sine, square, triangle, and plus or minus ramps; positive, negative pulses, and sawtooth outputs. And a host of other important features, too. Something for everyone.
Learn more about the unique aspects of this Function Generator line, write: The Wavemakers, Krohn-Hite Corporation,

580 Massachusetts Avenue, Cambridge,
Mass. 02139. Phone: (617) 491 -3211.
TWX: 710-320-6583. Wavemakers par
excellence.
"L-ILf lI KROHN-HITE C::: c::> F=t J:=>c::> ~ ,.00., , - I c::> ,.....,.
OSCILLATORSI FttlERS I AC SOURCl SI FUNCTION G£N£RATORSI AMPLIFIERS
OV ERSEAS SALES OFFICES: BELGIUM , C. N. Rood s. a.; DENMARK, SC Metric A/ S; FRANCE, Antare s; GERMANY, Nucletron Vertrie bs-GMB H; HOLLAND, C. N. Rood n. v.; ITALY, Dott . Ing . Mario V ianello; SWEDEN , Tele instr ument; ISRAEL , R. D. T. E lect. Eng . Ltd .; JAPAN , Shoshin Sho ji Kai sha, Ltd .; AUS TRALIA , Sample El ectronics (Vic.> Pty ., l td .; G. B., B & K In st. ltd .

Functions for
every~ne.

Odb

-10db

-20db -JOdb

-40db

)
I
GI. E+XvT
IUHllfG

-50db -60db -70db

Circle Reader Service #26
Pat. Applied For

Shown approx. same size.

The Los Gatos system has encountered exactly thi~ problem . The number of crossover filters have been reduced so that the luminance-chrominance delay is now acceptable. As of this writing, a 120-ns delay has been reached along a 3.9-mile-long trunk between a test home and the studio.
The time delay was measured by comparing a 'scope photo of the time positions of the luminance and chrominance signals as received at the studio with a reference photo made at the source (test home). Any time-position shift between the two photos is the result of delays added by the filters . The luminance signal was set to 31 MHz, and the chrominance signal to 34.58 MHz. Because the cutoff frequency of the crossover filters is 35 MHz, this was a worst-case test.
The crossover filters caused another problem . Fullbandwidth sweep testing of the entire system through 20 amplifiers and 5.5 miles of downstream trunk , between the head-end and the test home, showed that the filters disturbed the flatness of the system's downstream amplitude response. Reducing the number of filters from 54 to 40 in this run corrected the problem . The response is now flat within ± 1.5 dB, and acceptable, although such a run without filters could be held to ±0.75-dB flatness.
The result of these tests is that the system is now running with full downstream capability while simultaneously transmitting three color-signals upstream .
Data tests to begin Although some critics say that a 1-Mb/s data rate is too
high, TelePrompTer feels that it is entirely practical. And the company envisions a future system in which data can enter the upstream cable at any point for transmission to the head-end , where it would be turned around and sent downstream to wherever it has to go .
First tests of data transmission at Los Gatos will use a word generator as the data source. A modulator will convert the 1-mB/s data to a 4-MHz-wide rf signal on the upstream trunk . This data signal, variable in level and modulation depth, will be used to check error rates .
The downstream spectrum at ·Los Gatos includes a 4M Hz slot to transmit data to the test home. So TelePrompTer actually will be testing a two-way interactive data-handling system.
The home terminal used in these tests will be a generalpurpose prototype . Later, it can be altered to perform specific services in the home: meter reading; security alarms; and so forth . (As of this writing, the first data-transmission test results are not yet available.)
Multi-subscriber data transmission Later this year, TelePrompTer, working with Hughes,
plans a full-blown test of two-way data transmission in a 25-subscriber network . This test will include some hardcopy printers- models aimed ultimately at the low-cost market. Each home data terminal will have its own small memory (probably MOS), which will hold its inputs until in-
44

r------------,

-I
54·260MHz 1

,_ Prog ram mater ial , down stream I 54·260MHz

I

I

L

I

I

I

I

l ~Hz

I

: Downstream

I

1 ~z

I

I Upstream

L------------..J

~ 5-30 MHz

r-------------,

I
I
5- toO MHz

t74 -260 MHz

·--I
I
l t74·260MHz
I 5- tOOMHz

I L

L I

J L _ _ _ _ _ _ -5~0~M~ __

30- tOO MHz

Extending the spectrum. This is a dual-cable system in which one cable carries the normal , 54-260 MHz, downstream programming, while the other carries dual-directional (upstream and downstream) communications . Thus , in-dustrial users could have available the full cable spectrum for up- and downstream traffic, while home subscribers still have the 5-35 MHz region for their upstream use (feeder
lines in upper part of illustration). Further, the number of crossover filters needed is greatly reduced as compared to those needed in other schemes . This method will probably be investigated at Los Gatos .

terrogated under control of a central computer (probably a PDP-I I). Even though the subscriber's memory access is controlled by a central computer, the memory will be scanned often enough so that the subscriber feels he has continuous data transmission available.
By the end of 1972, TelePrompTer hopes to have a similar system fully equipped for several thou sand subscribers- only 18 months after the simple beginning at Los Gatos.

Thanks to ...

... Tom Ritter, director of research and development

for TelePrompTer (Lompoc, Calif.), and Bill Wagner, man-

ager, TelePrompTer of Los Gatos, for generous contribu-

tions of their scarce time .

e

INFORMATION RETRIEVAL Communications,
Data acquisition and processing
THE ELECTRONIC ENGINEER · June 1971

This new IEC IO MHz Function Generator has a couple of things going for it!
(like sweep &phase lock)
MUL.TIPUaR

And that's not all. Sweep and phase -lock are just two of the numerous features that distinguish this new IEC 0.0005 Hz to 10 MHz all-purpose test instrument. For example , trigger/gate, and calibrated output attenuation . The F55. The Great One . Top of the Series 50 line that includes four other brand new function generators . What do they have in common besides superb performance? 10 MHz capability, fixed and variable offset, variable width pulses as well as fixed width pulses and ramps , simpler man/ machine interface and much , much easier maintainability. That's what. Plus the special features of each model , such as the sweep and phase -lock blend of the F55.
Depending on requirements , there's a particular Series 50 model that's exactly right for your needs. And priced accordingly, from $595 up. Like a look? Call , TWX, write or w ire our John Norburg at Interstate today. Ask for a demonstration. Get a new IEC Function Generator going . For you .

F51
THE ELECTRONIC ENGINEER · June 1971

Circle Reader Service #27

45

RUJLT FEL\TLPE

L(]f:lPUTcA L[]~TA[]L
comes to network testing

Arthur J. Boyle, Technical Editor
The manufacturers of electronic equipment continue to cram more and more complex circuits into any given space. As they do, the problems of testing these crowded quarters grow very rapidly to unmanageable proportions. Consider, for example, testing the backpanel of a moderately complex piece of digital equipment. How do you test it with a reasonable degree of confidence? You can continuity check it with an ohmmeter, but this takes an inordinate amount of time. And , when you finish , all you know is that you do have continuity where you are supposed to have it. You do not know if any extra connections have been made; if for example, two supposedly separate circuits have been shorted together.
One approach to this problem is not to test at all at the subassembly level. You assume the backpanel is correctly wired and try to catch any errors during the final checkout of the equipment. Troubleshooting and repair time soon make this a very unattractive alternative.
A better way Teradyne Inc. of Boston, Mass .,
faced many of these same problems in the manufacture of the computer-controlled test systems which they produce for a wide variety of applications . With their experience in the application of computer control to testing problems, they reasoned that they should be able to 1.:ome up with a sensible solution. Well, they have done just that. And in addition to solving their own production problems, they have added the N 131 Network Tester to their product line.
The N 131 is a computer-operated test system which will test either 1152, 2304 or 3456 pins (interconnection points) depending on the configuration of the system . It tests a complex interconnection
46

Circle Reader Service #362
system of 2000 pins in just about 30s, and in addition to continuity, it checks for anv short circuits which might exist.
The NI JI system consists of the test instrument itself, a Teradyne M365 computer, a Teletype ASR-33 or -35 and a CartiFile magnetic tape unit. Operation is simple, and the communication between computer and operator is in an easy-to-understand format. Because of the system's self-learn capability, no programming is required when you begin to test a new network.
Five Teletype commands control the entire operation of the N 131 . They instruct it to I) learn a new interconnect system, 2) print a run list, 3) test a unit, 4) output a program from memory to mag tape, and 5) load a program from tape into memory.
Easy to operate As an example of the system oper-
ation, let's assume you have two production lines turning out backpanels for two different pieces of equipment. One of these is an established unit, and the other represents a new addition to your

product line. When the first new backpanel comes off the line, you connect it to the N 131 and command the system to learn the new panel. In a time about :qua! to testing time (30 s for 2000 pins), the computer maps the interconnection pattern for the panel. The next step is to command the computer' to print a run list. This list shows all the interconnections in the panel. You can then compare the run list with the original engineering documentation to verify if the panel was wired correctly. When you are satisfied that the computer has the correct interconnection pattern stored in memory, the job of testing successive panels becomes fairly simple. You connect them to the N 131 , and command the system to test them. T~e computer matches the new connection pattern against the stored one !ind prints out any differences. The printout, in conjunction with the run list , will usually allow you to pinpoint the error in minutes, instead of the hours it might normally take. When you are finished testing the new backpanels you output that program to magnetic tape and load in the stored pattern for the other panel.
The system has a nominal testing rate of 50 kHz. The voltage levels used are 5 V and ground, with a DTL driver /detector on each pin. You can use the system for testing backpanels, wiring harnesses for PC board cages, multilayer PC boards and most other interconnection system you might run across.
As mentioned earlier, the maximum number of points which a standard system will test is 3456. Teradyne says that they can supply larger systems on special order. The smallest system, 1152 pins , is priced at $48,500. You can add more capability in groups of 1152 pins for about $10,000 each up to the 3456 maximum . Teradyne Inc ., 183 Essex Boston, Mass. 02111.
Circle Reader Service #362

THE ELECTRONIC ENGINEER · June 1971

CAPACITANCE IN MICROFARADS
AT 120 Hz
ESR IN OHMS AT 120 Hz
DC LEAKAGE CURRENT IN MICROAMPS

75 MFD/30 VOLT DC CAPACITORS

______.____.___.______._______~!

:

i 1 - - - - - - - -

~:.s~ rf-?

1

.6

.4 i[l
.2 I .~
'.1
.os ..........
.06

.04

.02

0

2

4

,....--

/:\:

= """""

""

6

8

10

TIME IN THOUSANDS OF HOURS

"'
12

:Ji\

---

14

16

Our new TCG capacitor has curves·
you can't resist.

The curves tell at a glance the typical life story of one of our new TCG aluminum electrolytic capacitors. But there's more to a TCG than life curves. There are 45 case sizes, with safety vent protection where required; capacitances from 2 to 22,000 mfd; voltages from 3 to 450 VDC; and a -40_to +s5°C temperature range.

Add to these a high C/ V in a small package. Plus outstanding electrical and physical characteristics. And you've got our new TCG. Find out more by writing for Bulletin 4-307. Eighteen pages of data , .· and some curves that will open your eyes. Popular ratings available from authorized Mallory distributors.

MALLORY

MALLORY CAPACITOR COMPANY
a division of P . R . MALLORY & CO. INC.
Box 372, lndlanapolls, Indiana 46206; Telephone: 317-636-5363

Electrical and electronic components · sequence timers · metallurgical products · batteries

THE ELECTRONIC ENGINEER · June 1971

Circle Reader Service #28

47

UN-BURDEN System Costs UN-BUCKLE Software Shackles UN-CORK Design Creativity with Ferroxcube's new UN-COMPUTER TM
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FOR: PROCESS CONTROL, DATA ACQUISITION, DATA REDUCTION, DATA MANIPULATION, BUSINESS SYSTEMS, SCIENTIFIC INSTRUMEN TATION, DATA- LINK INTERFACING, DIAGNOSTIC TESTING, DATA RE- · TRIEVAL & EDITING

The odds are 2 to I that your system doesn't need a minicomputer. That's right-in 2 out of 3 applications, you can save from $5,000 to $15,000 per system, and get more interface flexibility ... higher reliability . .. lower software costs (if any!) ... and much greater freedom from hardware restraintsby designing around Ferroxcube's unique, completely modular UN-COMPUTER. TM
UN-COMPUTERS do more-and let you do more-than arithmetically oriented, general-purpose machines, with their over-committment to the

central-processor interface. Check the UN-COMPUTER's block diagram . When you consider that every block is an independent option, you'll understand why we say that, for many applications, the minicomputer is a tragic misfit.

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48

Circle Reader Service #29

NORTH AMERICAN PHILIP')
±.! '.ff
THE ELECTRONIC ENGINEER · June 1971

MEMORIES COURSE · PART5
MEMORIES:
Bulk storage

Steve Thompson, Western Editor, Los Angeles
In parts 3 and 4 of our course, we were concerned with computer mainframe memories. These are the storage locations which hold the program and data with which the computer is currently working. Now, in part 5, we are going to turn our attention to a different application- bulk memories .
You can think of mainframe memories as being the reference books on your desk . As you work on a design, you const;i.ntly refer to them for information. If you carry the analogy a bit farther, bulk memories would be equivalent to your company library. When you start a new project, you go the the library (bulk storage) for new reference

books (blocks of data) and transfer them to your desk (your
mainframe storage.) The important considerations in a bulk memory are .how much information it can store and at what cost. Access time is not as important as in the mainframe because the computer does not go to the memory as often . Also, when a bulk memory is accessed, large blocks of data are transferred, rather than just the contents of one or two locations.
The graph below shows a number of bulk memory types differentiated by access time and by cost. If you look at the graph, you will find a no-man 's land between cores and discs/drums. A market exists for the engineer-entrepeneur who develops a cost effective memory with an access time hetween 1 µs and ·1 ms.

Sem iconductor

BULK STORAG E TECHNOLOGIES

Approx . cost (¢/ bit)

' OJ

003

0 .0 0 1

0 .0001

~----~ · 1 ~----~I~----~ ~----~I r - - - - - - , I r - - - - - - ,

Magnetic care 8 f ilm

Head/ track discs 8
drums

Moving head di scs 8
doma in wall

F ilm or magnet ic
str ip

Mag net ic
8 laser tape

Magnet ic
cards, paper tape 8 card s

:Jt.::

I

I

I

100ns

1µ.s !ms

10ms

200ms

ts

min

Courtesy of lomec Inc., Santa Clara, Calif.

Approx . access time

Punched paper cards

Dr. J. A. Carlson, IBM Gene ral Systems Div .. Rochester. Minn .

the first card machines to be used in data processing for

the U .S. Census Bureau, and in 1896 he started the Tabu-

The punched paper card has a long history as a means of

lating Machine Co ., which became a part of IBM Corp.

r

conveying input. The Jacquard mechanism , developed in

James Powers also developed data processing machines

1801 , was the first device to use punched cards. The mech-

while working for the Cens us Burea u. They were used in

anism controlled the operation of a loom , and the punched

the 1910 census , and in 1911 he formed the Powers Ac-

cards generated the weaving pattern. Later, in 1833, Bab-

counting Machine Co ., now the Univac Division of

bage's design of a mechanical computer used Jacquard

Sperry-Rand.

cards as input. In l880's, Dr. Herman Hollerith developed

Both I BM and Univac adopted 3 1/.i by 7 Vs in cards with

THE ELECTRONIC ENGINEER · June 1971

49

MEMOR IES COURSE · PART5

45 columns of 12 holes. Univac used each column to store two six-bit characters, producing a 90-column card. The present 80-column, 12-hole card, was introduced by IBM in 1928 . These cards featured rectangular instead of round holes to match the parallel brush reading technique. Billions of these cards are used each year.
A smaller, 32-column, 18-hole card was introduced by IBM in 1969. The 18 rows are divided into three groups of six holes each. This gives the card, in effect 96 columns. Because it measures only 2 Vs by 3 1/.i in ., the card significantly reduces storage and machine size.
Since punched cards may also carry color coded or printed information , these cards represent a circulating bulk storage that humans and data-processing systems may interact with . Pre-printed cards sell at about $1 or $0 .8 7 per thousand for 80- and 96-column types, respectively . If each hole location is a potential bit, that approaches 0.0001¢/ bit.
Unit records and files
Since a card can be physically separated from the others, each card becomes a unit record . Assembled records, in turn , constitute a file . Small files are called decks, though some program decks have thousands of cards. Card files allow manual access and modification , which is very advantageous in preparing computer programs . Other examples of files are payrolls, inventories, name and address lists, and parts on order.
A " field " is a gro up of consecutive columns containing specific data such as a name or number. It can range from one to all the columns on the card. When a computer reads a card , it stores the fields in its own memory fields for subsequent processing. Computers may also compose cards by transferrin g fields to cards via an output card pun c h .
A minimum unit record data-processing system consists of a keypunch , sorter, and accounting machine. With these, cards are punched ; files are sequenced, combined, or separated ; calculation s are performed ; and reports and results are printed out. A minim um system costs about $24,000 or rents for about $350 per month . Larger, higher speed systems cost $55,000 or $1,400 per month and up . They can operate at speeds up to 2,000 cards/ min for

reading and sorting, and 500 cards/mi n fo r pun ching. Lower priced computer systems tend to displace the la rge r unit record card systems.
Punched cards represent the predominant fo rm of bulk storage in data-processing fro m 1890 to about 1960, and still represent a low-cost, versatile approach to data processing for the smaller user. Since card machines are lim ited by speed other forms of bulk storage have beco me more economical as volume and card handling increase.
The IBM 80-column (a bove) and 96-column (below) pu nched ca rds . Eac h type uses diffe rent coding syste ms, a nd some cards use more t han one code. The Uni vac card employs the si x-bit Powers Code. Hollerit h devised a code usi ng 10 of the 12 rows of the la rge ca rd for numbers 0-9. and add it ional pu nc hes in rows 11 and 12 for al phabetic a nd s pec ia l cha racters. Additiona l specia l c ha racters require th ree punches in a co lumn . By usi ng .a six- bit binary code, the 80-colum ns beco me 160 col umns ' cards . which is often done when sto ring progra ms in machine la nguage. A six-bit code is used for the System/ 3, 96-column card. Writing is done by mecha nica l punc hing; reading is done by sensi ng the presence or a bsence of light as hole positions pass over light so urces.

Paper tape
Contributed by Tall y Corp., Kent, Wash.
Think of a paper tape as an extended paper card. Punching rates are about 400 characters per second (cps) for cards and 300 cps for tape . Cards can be read at speeds up to 3,000 cps, and tape, up to 1,000 cps. However, the effective rates for cards are somewhat lower than these numbers, because indicator information is needed at the begin ning of each card and unused portions are also processed. Choosing between the two types of memory media is based on the application, not on speed .
50

If your problem is handling recorded data with message lengths less than the capacity of a card, consider cards as the storage media. The chief advantage of cards is th at they can be easi ly sorted, merged, and rearranged without re-recording. On the other hand, paper ta pe is desira ble for recording variable record lengths with no efficiency loss. Tape data offers ease of handlin g a nd storage, a nd relative safety from loss . Simu ltaneous preparati on of tapes and original doc uments saves an encod ing step .
If you can work serially at reading rates less than 1,000
THE ELECTRO NIC ENGI NEER · June 1971

cps and wntmg rates below 300 cps for long and short messages, paper tape is the most cost-effective answer. When serial read / write requirements go higher, magnetic tape becomes attractive.
Paper tape readers sense the presence or absence of holes, either mechanically or photoelectricall y. (The classic starwh eel mechanica l reader is shown in the figure.) Tape transport, inertia, and contact bounce limit their reliable reading speed to 150 cps. Paper tearing can also be a problem . Photoelectric readers operate in the 300- 1,000 cps area . Although they are gaining popul arity because of cost reductions and speed, these readers are limited by res ponse time of the photocell and tape transport mechanisms.
One in . wide, eight channel tape is standard , though five, six and seven channel types are also used . Dependin g on the reader's sensing method , a paper tape is good fo r between 300-3,000 passes . If more passes are anticipated , you should switch to MylarTM tape or an equivalent, which is good for up to 50,000 passes.
One of the leading uses of paper tape is in the machine tool industry in numerica l control machines . They are also widely used in process control , automatic testing, input to digital computers, and automatic message transmissio n applications .

The Tally Form C contact reader and st ar wheel
mechanism. Each channe l has a st ar wheel and carrier arm . If no hole is present, the wheel slides along the tape without turnin g. Upon con t act w it h a se ri es of holes, the wheel rotates with the points dropping into successive holes . Con t acts switch on ly when a wheel moves from a ho le t o a no-hole . or vice-versa.

Magnetic tape

Edward S. Kinney ,

drum s begi n to co me into their own.

Co mputer Products Di v.. Ampex Corp ., Culver Cit y. Calif.

Since mag tape is used as a communication media be-

tween processors, standards have evolved which govern the

Magnetic tape has been used in all storage areas, and for

mechanical properties of the tape a nd the information for-

longer than any other media in EDP except paper cards and

matting . Two standardized form s of tape are used for data

paper tape. Of all the storage media, it is the more ef-

interchange: 1/2-in. computer grade on reels, and 0. 150-in .

ficient in terms of cost per bit and total storage space for

tape in cassettes . Most tape is the 1/2 -in . standard . A reel

archival storage . Among the most suitable applications fo r

of tape should be considered as a sub-assembly consisting

magnetic tape are infrequently queried master files and

of the reel, write enable ring, mag tape, and the BOT (be-

non-volatile archi val storage, such as address fil es and

gin ning of tape) and EOT (end of tape) markers.

geophysical data . The advantages in clude its applicability

Ma nufacturers certify the usable area of the tape. This

to offlin e data retrieval and processing, and the availability

process usua ll y includes writing an all-1 's pattern at the

of low-cost, low-speed tape.

certi fication den sity of 200, 556, or 800 bits/ in . or 3,200

It is easy to design a tape-processed file. New in-

flux changes / in . and determining bit " drop outs" or "drop

s~allati ons become operati onal quickly and subsequent up-

ins" on a read -after-write basis. An important factor is

gradin g of tape perfo rm a nce does not req uire C PU repro-

surface resistance which must be controlled to reduce stat-

gra mming. Those EDP tasks req uir ing aud it ing functions ,

ic electricity that builds up during operation.

and most sorting a lgo rithms, are performed more ef-

In operation, mag tape has only two magnet ic states

ficiently when mag tape is the storage and manipulation

representi ng saturation of the magnetic particles in either

media .

of two possible directions. There are three basic tape for-

Although mag tape system costs much more than a pa-

mats . Seven and nine track formats are standard (six or

per card or paper tape system, it provides a speed advan-

eight bits plus a parity bit) . though an eight track format is

f

tage . When information can be organi zed into independent

sometimes used . The standard length of a reel of tape is

blocks that do not require much cross-referencing, tape is

2,400 ft. Up to 1,600 bits/ in . can be recorded at tape

a satisfactory and inexpensive storage method . When pro-

speeds up to 200 in./s. This means th at up to 4 x 108 bits

grams require skippin g aro und from block to block , the

can be stored on a tape with an average access time of 72 s.

linear nat ure of tape and the time requ ired to pass over ir-

Tape costs abo ut $ 12- 15/ reel, or abo ut 0.001¢ / bit.

relevant data block s make it inefficient, and discs and

Data us usuall y written in blocks , with a ppropriate

THE ELECTRONIC ENGINEER · June 1971

51

MEMORIES COURSE · PART 5

check characters and inter-block gaps of about 3/.i in. The gaps provide time for stopping the tape after a read process, and time for the tape to come up to speed prior to reading the first character in the next block of data. This imposes severe acceleration and deceleration requirements on the tape, which the tape can meet , but the reels cannot, even empty.
The two methods to buffer the reels from the capstan

system are illustrated . There are significant advantages to the vacuum storage method since the mass of air is negligible at most tape speeds. Thus, transient loading or pressure on the tape is minimal. Economical, mechanical buffering ca n be effectively used below 24 in ./ s. Any system requiring extensive intermittent tape motion should use vacu um buffering to significan tl y reduce tape wear.

' "">D roller
o. Pinch roller drive

V PseonssCornst

~

Two-gap reod / wr ileheod

b. Vacuum buffering

i

Vacuum

c. Mechanical arm buffering

Transports and buffers. In a, the capstans co nstantly rotate and tape motion is ach ieved by pinch roller act io n. These older, dual capstan systems intermittently pulled tapes into contact with moving surfaces, giving rise to slipping and tape surface wear. In b. and c, high torque, low inertia motors enable si ngle capstans to be constantly in contact with the tape , yet start and stop rapidly enough for proper motion control. Buffers are essential to isolate a section of tape from the reels, since the moment of inertia of the
tape is orde rs of magnitude below that of even an empty reel . The actual encoding, reading, and era sing occur at the read / write station . The two-ga p head reads and writes at different gaps, offering advantages in validity c hecking. Changing th e polarity of the write current changes the magnetic polarity induced in the magnetic oxide layer, co rre sponding to ls an d Os.

Optical/thermal mass-memory

Harold Dell , Prec1s1on Inst rument Co.. Palo Al to. Ca l if.
The UNICON® (unidensity coherent laser radiation) mass-memory system is a peripheral memory for large and medium scale computers . It ca n write, store, and retrieve 10 " bits online. This is the equivalent of 10,000 reels of 800 b/ in. mag tape. User costs are less than 0.0002c/ bit. The system reads and writes arc hi val-type reco rds, which are permanent and eas il y updated .
A finely focused laser beam writes binary data in an extremely dense format on a special recording medium ca ll ed Data StripTM. The system uses 400 strips, housed in 16 groups of 25, with provisions for a n additio na l 50 strips.
To write, a lens focuses the laser beam onto an area which is a few microns square. Incoming data modul ates the beam such that a 1 intensifies it, causing it to vaporize a minute hole in the strip's metallic surface, while a 0 does not cause any hole . Thus, we have an optical/ thermal recorder.
The strip, which is mounted on a revolving drum, allows
52

A Data StripTM is a polyester sheet with a thin metallic coa ting. It is 31.25 x 4.75 x 0.007 in. One strip stores 26.8 million b/ in 2, or 2.88 billion bits for the entire strip .
THE ELECTRONIC ENGINEER · June 1971

262,460 bits to be written seriall y a long a track the length of the st rip. A bea m lens carriage moves incrementall y across the strip, writing up to I 1,000 seq uential tracks. To read, bea m intensity is maintained at the wri te-0 level and directed at the desi red track. Renected light from the strip , or lac k of light from vaporized portio ns, constitute~ the serial read data pattern. Through a read-while-write verification ca pability, a portion of the renected lase r

beam is used to check written dat a by co mparin g it to the origina l input. The un co rrec ted erro r rate averages o ne e rro r in I 0 ' bits.
Average access time for a m ount ed strip is 150 ms. It takes a maximum of 8.6 s to cha nge a strip on the drum . The data rate bet ween the system a nd the host co mputer is 4 million b/ s.

Host c
0
m p u t e r
Channel control

To chann el 2
Co n t r o l computer

Channel 2 strip load/unload control Carousel postion control
Channel t strip load/unload control

· I
Carousel

Beam splitter

Laser Source

Word processo r

Drum control

Car ri age / galvanometer control

Strip drum

1411······.i Buffer
co re

Read/write ~-········
and error

mem ory

co ntrol >-------<Modulator

Legend Optica l path
Mechanical path
Com mand and control path
Dato path

Recorder control unit

Lose r recorder unit

The optic al/t her ma l memory co nsis t s of a Lase r Reco rder Unit (LRU ) . whi ch ca rri es out the read/ write fun c tion s, and a Recorder Control Un it (RCU) , which se rves as the file manager and controls the LRU . The LRU co nsi sts of a ca rou se l rota ry file with up to 450 data strips and tw o read / write chan ne ls (on ly Cha nnel 1 is shown) . After the laser beam is split. it is se nt to each of the two read/ wr ite channels. Each cha nnel has a laser modulator . drum . and ca rr iage. Stati ona ry mirrors direct the beam t o a m ova ble, se rvo-co ntrolled ca rr iage where a galva nometer-co ntrolled mirror reflects the beam thr o ugh a microscope lens. The c onverging lens pinpoints the beam on th e surface of the rotating data strip. The RCU ha s a con trol co m -

puter that is common to both channels, and one word proce ss or. buffer co re memory , read/ write and err or co ntrol subsys tem , and 1/ 0 control per channel. The buffer co re memory accommodates disparities in data rate between the host co mputer and the massmemory system . The host computer can ope rate with other peripherals while the m ass- memory system is locating data. It then perm its co ntinual read / write operation for as long as required at the maximum data transfer rate of the mass- memory system . The read / write and error control logi c, whi c h detects in co rrectly written bits, directs th at the erroneo us word be rewritten .

Magnetic discs
William Be rtrando, Appl ied Magnetics Corp.. Goleta. Cali f. Disc and mag tape memories use similar codes to sto re data. These codes can be either one of two types: non-return to zero (NRZ) or phase modulation. Although bot h sto re digital data on the surface of a magnetic medium ,
THE ELECTRONIC ENGINEER · June 1971

discs can be used as computer mai n memory extensions a nd o n-line memory banks, because th e average access time is a bo ut I0 ms . Discs a re fin ding increased usage as fast-access co nce ntrators for vis uall y o r gra phica ll y displayed data.
53

MEMORIES COURSE · PART5

T here a re two types of disc mem ories : head-per-track (fixed head), and movable head. Both types of heads are des igned to " Oy" 20 to 100 µin . above the disc which may m ove at relati ve speeds near l20 mph .
By saving on heads, which are precision devices, mova ble head memories are less expensive. Some of this saving is o ffset by th e cost of a precision head-posi ti onin g assembl y. The average access time for a fixed- head disc is the time for one-half a revolution. This is much faster than a m ovable-head disc, because the movable-head disc must add the time it takes to first pos ition the head over the pro per track . Mova bl e- head discs have a Oexibility advan-

tage because they can be removed from the drive assembl y and st~red, or transported to other locations for use with compatible disc dri ves.
Movable-head types have been th t most popular, especia ll y with large computer users. With the advent of minico mputers, lower head costs, and faster access time requirements, fixed-head disc usage is projected to increase rapid ly. Naturall y, as disc diameter increases, storage capacity incn:ases. Discs up to 40 in . in di a meter are available . Generally, while the price of a disc memory increases as storage density increases, the cost per stored bit decreases .

Fixed head or assembly of heads

Data wr ite amp lifier

Data read amplifier a. Fixed - head disc memory
Movable head 8. dire ction of motion

Disc center line

Head actuator or actuators
b. Movable -head disc memory
Fixed and movable heads . T he fixed -head disc memory has st at ionary magnetic heads, or an assembly of fr om one to 16 head s (head modul e), pl aced directl y ove r each da t a tra c k in the usab le di sc surface. Movable-head memories have on ly one head pe r surface, which moves radi al ly to the pr ope r tra c k.

Magnetic disc cross -section . Nickel-cobalt is the normal disc coa ting with a hard coa t ing app lied over this magnetic materi al to fo r m a surface for " flying" (and " landing") the hea ds. Passing current through one or the oth er winding of the m agnetic head creates a directi onal m agnet ic flux at the head gap, which magnetizes the di sc area directly benea th the head. The tw o poss ible directi ons are ass igned bit va lues 1 o r 0. Bits are read by sen si ng and amplifying emf changes in the co re win din gs produced by flux reve rsals as they pa ss by the head .

Disc organization . Thi s typi ca l fi xed-head disc memory uses eight head m od ul es of nine heads each. Th e n inth head in each module is a spare. In add iti on to the 64 data trac k heads, a cloc k module con t ains three hea ds for th e o ri gin, sec tor, and bi t c lock tracks. The o r igin cloc k is an "in dex" or " marker " that occ urs once every revolution . The sector clock ind ica t es the start of a word or bl ock of data. Th e bit clock indicates a bit ce ll a nd may occur from 16,000 to ove r 100,000 t imes per revol ut ion , depending on the memory . Clocks are ca librated informa ti on, so the typical disc is deli ve red with th e c loc ks wr itte n on the disc in th e c ustome r's for m at.

54

THE ELECT RONI C EN GINEER · Jun e 1971

0 0 0

I I I I

NRZ1

Non-return-to-zero

Phase modulation

Coding techniques for recording data. The NRZ format separates into "straight" NRZ and NRZl (invert , or change on l 's). In straight NRZ, which is the most common , a flux transition indicates a change from a
0 to a 1, or vice versa . The electronics for determ ining bit cell contents are complex, because it is diffi c ult to
determine which way the flux transitions occur, and
data is not self-clocking. In NRZl, flux transitions occur o nly when a 1 is
record.ed . This eliminates the ambiguity of the
straight NRZ method , since signals will only occur for l 's and not for O's . The electronics for determin ing
bit cell position are also complex, but the complexity
is justified because both types of NRZ increase the bit density by a factor of two compared to phase modu-
lation . Phase-modulation coding is separated into Man-
chester and double-frequency techniques. Both techniques require at least one flux transition per bit . In Manchester, the write signal for a 1 is high duri ng the
first half of the pit cell and low during the. seco nd half. It is reversed for a 0 . In double frequency, a 1 requires two transiti ons per bit and a 0 requ ires o ne. Phase modulation has a built-in cloc k, which simplifies read electronics , however , there are twice as many flux transitions as NRZ, so the information de nsity is only one-half.

The silicon drum
Dale A. Mrazek, 'National Sem iconductor Corp., Santa Clara. Cali f.
Solid-state counterparts of small disc and drum memories have become practical with MOS/LSI. Because most of the co nt rol logic is provided on the monolithic chip, the otherwise very high logic "overhead" is kept to a reaso nable level. Costs are a penny a bit , or less, up to several hundred kilobits . In the megabit range, cost-effectiveness depe nds on rapid access, minimu m data-transfer delays, a nd operati ng m odes geared to the parent processo r.
Basic "silicon drum"
The first figure shows a silicon rendition of a drum memo ry. This simple orga ni zation for tens of kilobits can be extended by adding more registers in parallel, or using lo nge r registers. Neither method is practical beyond hundreds of kilobits. Adding parallel registers complicates the switching matrices; longer registers increase access time a nd force the cont ro l logic to keep trac k of several 0-bit locati ons per bloc k.
The cloc k frequency is mod ul ated in large sys tems to minimize power d issipation. T his modulati o n, however, is inefficient if many blocks are stored synchronously. Clock mod ul atio n means the registers are o perated as a low idl e freque ncy (abo ut 500 Hz) . When a reg ister is addressed , that register is operated with a much faster clock to make an access or transfer. H igh/low freq uency ratios such as 2 M Hz/ 2 kHz reduce average power dissipation from about 0.5 mW to a bout 1.5 11W / bit in large systems.
Word-parallel memories
Today's megabit systems are based on the bit-block par-
THE ELECTRONI C ENGINEER · June 1971

a llel approach, because most processors use that format. When n sy nchron ous registers operate in parallel , each clock period represents an n-bit block address. All register inputs or o utputs must be enabled and the serial / parallel conversions co mpleted in one clock period.
Because a memory with 256 blocks of 5 12, 16-bit words would take 8, i92 registers lined up, the 2 D organization is a bandoned in favor of 3D; that is, several sy nchronous storage planes are used . With this approach, access and transfer times come out to be well under a millisecond . Clock modu lation is efficient in this case, because there are many parallel-accessed registers per plane, and the counter control monitors the same 0-bit location everywhere. Each individual block requires n 1/ 0 switches.
One very serious problem with a memory such as this is that large numbers of MOS o utputs cannot be bus-connected an d operate at high speed . In order to overcome the high capacitive load ing on the driving outp ut , the clock period, must be extended .
A solu tion to this prob lem is the tri-state logic concept, origi nated by the a uth or and his co-workers. The o utput element has three logic stat es : 0 or I when the outp ut is enabled , or a high-impedance state when it is disabled . The third state is almost an open circuit, so only microamperes of leakage fl ow through the package's data-bus output pin . When ena bled , MOS o utputs can so urce or s ink man·y such leakage currents. When eight outputs a re bus-connected, any one can drive the bus a nd a TTL load at up to 2.5 MHz.
Only a few packages are needed , since the devices do not have to be sub-mu ltiplexed . They can be connected 128wide to the major bus a nd switched by the address bits de-
55

MEMORIES COURSE · PART5

fin ing th e module size . Speed decreases in proport ion to th e additional connecti ons. For 128 outputs, the max imum is about 500 kH z. At this rate, worst-case access and tr ansfe r times will ran ge fr om a bout 1 ms fo r 256-word bl ocks, to 4 ms fo r 1024-word bl ocks, which is fast fo r a peripheral memory.
Cost effectiveness As ca pacity increases into th e mega bit range, register

sto rage enters th e gray area where speed vers us cost determines th e techn ology choice. One rul e of thumb states th at the cost ratio can increase as the squ are root of the speed i mprovement ratio. An order of mag nitude improvement in speed makes th e memory worth three times as much.
The MOS memory soo n bumps into still fa ster memory tec hn ologies , such as bip ola r RAMS . If bipl oa r a rra ys should reach th e ca pacities of dynamic MOS reg isters, bl ock storage can be re work ed to accommodate th em, still res ult ing in a "sil ico n drum ."

0 \ 2
·0;:
~"'
]!
~ 0 Cl.

0 1 2
]!
. ~
0a.
' ~
~
(/)

f ~ig~kspeed -<!>--- - - - - - - - - - - '
Generic drum-type memory. Eac h of M sync hron ously clocked registers serially sto res an entire bloc k of N words , n bits long. Data recirc ulates , simu latin g drum rotation . Access is m ade by detecting th e 0-bit location (bit 0 of word 0) of the block with the counter. The in put or output of th e selected regist er is ena bled when t he 0 bit is at the outp ut. During write, ol d data is du mped by ga t ing off the rec irc ul at ion inpu t. The gate on the c loc k drive r minimizes power diss ipati on t hrough c lock mod ul ation . Average access time is one-ha lf a complete reci rc ulati on, or 0.5 TNn , wh ere T is the c lock peri od. Tran sfer t ime after in put or out put enable is TNn , since the c loc k rate is the seria l bit rate . On ly the add res sed bl oc k reci rc u lates at th e high f req uen cy, f , d urin g an acc ess and data tr ansfer . Access and tran sfer are c ompleted within one or t wo low-frequenc y cloc k per iods when f is a m ultiple of the lower on e. Generally , f is c hosen fo r opt imum data transfer . A minimum sa fe cloc k rate for dat a ret ention determines t he low freq uen cy . The low frequ ency ca n be a f ew kilohertz , and f , a few m egahert z . Eac h reg ister need s a dr iver. You must t radeo ff un used drivers for short r egisters versus increas ed acces s time for larger regi sters.

Recirculation loo

0

"::>'
0

"::>'

.0

'O 0
~

:0

:;

c' :

0

Read enable

Common clock

Read

dri ver

· add ress

f / 2N

f/ MN

Bit-parallel, block-parallel storage. A syn chro nous arra y of n registers with M bloc ks of N word s si mpli fies 1/0 sw itc h ing, el imin at es the par all el-s eria l co nverters, and red uces delays. but m ay pr event cloc k m odul ati on from keepin g power dissi pati on low . To acc ess on e of M bloc ks circ ulating through all registers requires a co unter-decoder logic network th at enables the swi tch ing when the 0-bit of the addressed block is at the register input for write or output for
read . Access ti m e imp roves beca use M blocks of N
word s will probably be shorter th an Nn-lo ng regist ers. Tr ansfer t ime shortens by a fac to r o f n . si nce the cloc k rate is the word rate, rather t ha n t he bit ra te. Logic co mplexi ty grows with M and th e comm on cloc k frequency prec lu des cloc k m od ulati on . Mem ory de lays are sho rten ed, but not t o an optim um level.

56

T HE ELECT RONIC EN GI NEER · June 19 71

Dynamic MOS RAMs for bulk memori·es

8. D. Broeker , Sem iconductor Prod ucts Div.. Motorola Inc.. Phoenix. Ar iz.
Integra ted shi ft regis ters ca n prov ide inex pe nsive, reaso na bl y fas t, sequ enti a l access bulk mem ories . Based on powe r a nd cos t , d yna m ic regis ters a re preferred over sta ti c registers, but both have the sa me dr a wbac k as oth er bulk sto rage techniques. There is a n uncert a in delay time befo re getting to a ra nd o m mem ory address.
Dynamic RAM S overco m e thi s draw bac k. The MOS d yna mic RAM, which req ui res lo w sta ndby power, gives ra pid access to a ny locati on. When sequentia l access to bl oc ks of data is desi red , the peripheral logic that run s th e dyna mic

devices ca n be red uced to a n insignifi cant fac to r , o nce the rand o m sta rtin g po int is determi ned .
U nlik e th e d yna mic shift register, mu ch 1/ 0 c irc uit ry is requ ired o n the chip to interface with the d ynamic RAM cell. Th is reduces th e size adva ntage o f the RAM , particul a rly fo r sm a ller mem o ri es . Th e advantage at 1024 bits is rn a rg in a l; a t 2048 o r 4096 bits, it is impo rtant.
Goi ng th rough the design of a bulk memory system as sho wn in the fig ure, dem o nst rates th e ve rsatilit y o f d ynamic RAMS , which a re eco no micall y fe as ible for bu lk mem ories, as we ll as minico mpu ter m ai nfr a mes .

Read / write Chip select
Data in Do to out - - - ....J
Re set

-rn:+-+ e r

Storoge array

Ccl 1

Col n Col 32

Refreshing a 1024-bit dynamic RAM . The memory wi ll only ret ai n dat a inde f ini tely if ea ch c ol um n is refreshed at least on c e every 2 ms . The <t> l clock signa l tr ansf ers o ne co l u mn of the 32 -bit by 32-co lumn ar ~ ay in t o a buffer st o ra ge co lumn , and <1> 2 tra ns fers it ba c k into t he selected col umn of t he arr ay . These tra nsfers refr es h th e ga te ca pac itance st orage elements . whi c h wil l now ho ld da t a fo r anot he r 2 m s. Sin ce re ading and writin g ar e usuall y done with a <1> l -<1> 2 cycle , a read or wr it e cycle also re fres hes one co lumn . If add res sing does no t se lec t ea c h co lum n every 2 m s, per iph eral elec tr onics are requ ired t o en sure per iodi c refresh . Th ese boo kkeeping electr o nics are an in signif ican t fac t o r in t ot al sys tem cost.
Buffers

1- of-16 decod e
i--------t_____J-1 "o"
~1------f-----... __ - - r~

t of 16 de cod e

16 lines

T HE ELECTRO NIC ENG IN EER · June 19 71

Block si ze

02 03 4 -bit sh ift
reg iste r
DP 2

02 0 3

4 - bit shift r e g is ter

M

Phase generation

0 Refresh 6 beekeeping

0 To / from CPU
(:>- To mem ory cord ·

57

'MEMORIES COURSE · PART 5

I 100 ns I 100 ns

100 ns

100 ns

100 ns I 100 ns I 100 ns

100 ns I

\~/~~~~~~\

/~~~~

Reset

Chip select
Write cycle read/write
Read cycle read / write

Don't care Don't ca re

Don't ca re Don't care

Control logic for I-megabyte storage system . This system off ers a random starting point and seq uential access to bloc ks of data . It is organ ized as 256K words by 32 bits (K = 1024), totaling 8,388,608 bits . It outputs four bytes (eight bits each) si multaneously. Bulk memories usually access a block of data , so the address inp uts are a start ing loca t ion and the block size. After a startup time of abo ut 1 112 cycles , dat a words appear sequen ti al ly at a rate of one word (fo u·r bytes) per cycle (abo ut 800 ns). The storage devices are arranged 32 to a ca rd , with 16 ca rds per "cage" and 16 cages per system . The eight most signi fi cant address bits drive two one-o f- 16 decoders, which select one ca rd in the 16 by 16 array. The 10 least significant bits go directl y to the memory devices. The five least significant of these bits are the col um n addresses, whi le the other five are the row addres ses. A sync hronous co unter is loaded with the co mplement of the block size and is incremented each cyc le . When the co unter reaches its maximum co unt. the desired number of words have been sequenced, and the memory provides an output . The carry-ahead enable signal stops the system c lock. To derive phase signals <t> l and <t> 2. an eight-bit shift regi ster obtains the eight 100-ns segmen ts. Word 01111111 is loaded into the register . The 0 shifts to th e ri gh t as 1's back fill . The

required logic fun ctions are obtained fr om NANO gates as the 0 propagates down the register . The outputs from the mem ory are later inverted with MOS-toTTL translators. A DATA VALID signal tells the processor when the output data is valid for a read cycle and when the input data may be removed f or a write cyc le . The ph ase signal-ge neration circuit is also . a clock controller, which ties into the refresh bookkeeper. The si mple refresh circ uit increments the address co unter and sta rts a read cycle once every 62.4 µs , to ensure that every five-bit co lumn address has one refresh cyc le every 2 ms. The absol ute address in th e co unter is unimportant , si nce only the first five bits determine the co lumn address . In normal read or write operati ons, the memori es are sequenced automatically and the refresh c irc uitry has no fun ction . By usi ng a retriggerable one-shot. keyed to the phase signa l generator, a refresh cyc le will only be ge nerated if no other cycle has occ urred wi t hin the pulse tim e of th e one shot. Thi s memory has 22 IC packages . The only other c irc uits req uired are TTL t o MOS tran slators and 32 ou tput buffer gates. The total cost
of the TTL cont rol logic is just over $100 in low quantities, or O.OOl e/bit. The major costs are in the board and hardware used t o co ntain the electr onics .

Domain wall memory
Bern e D. Broadbent , ·D, gi tal Devel opment Corp.. San Diego. Calif. A unique property of ferromag neti c material is that it consists of sm all regions called domains, each of which acts like an individual magnet. Taking advantage o f this property, memory devices ca n be co nstructed which store information by m eans o f the m oti on o f the transition area (referred to as domain walls) between domains . These domain wall devices are emerging as ve r satile, reliable lowmaintenance, non-mechanical mem ori es fo r com pact bulk storage at m oderate speed . The appropriate size range is from thousands to billions of bits .
One such domain wa ll motion memory i s the DYNA-
58

BITTM It uses magnetic wire as the storage element, and the domain walls propagate down the wire, much as bit s propagate through a shift regi ster.
Bit density is limited by the minimum domain size. Each dom ain has its ·o wn demagnetizing field, which beco mes larger than its threshold field , Hn , at som e minimum size, causing the domain walls to co llapse. Available m emories contain about 1,000 b/ in 3·
The larger the ex ternal magnetic field , H , the faster the domain m oves, and the faster the bit rate . Materials with high values of Hn and low values of Hw (thresh old level for wall motion) are used to maximize the bit rate . The
Circle Reader Service #32____.

This is a 64 word by 2 bit memory chip. Very fast: twenty nanoseconds access time. Uses very little power: less than half a milliwatt per bit. Very low cost: less than any other memory chip in its speed range. Very immediate delivery. It is hermetically sealed. Its thirty solder points make it easy to assemble automatically into either single or multiple chip arrays. It is undecoded. That means we can do worst case testing at the

chip level and improve package level yield and reliability. We run more than 250,000 tests on each chip before packaging. And our Phoenix production facility is now turning out these chips at the rate of five million bits per day.
Take two of these and what do you get?

MEMORIES COURSE · PART5

Atomic moments

Domain wall

b.

Atomic moments

Domain wol I

o-

I
.L -

-

r/-

0.

- )-

-)

~ ---- ----- '\

H --..::!-.---

b.

Ferromagnetic material consists of small region s, ca lled domains, each acting like a tiny magnet. When unmagnetized , their poles are randomly oriented, giving a net magnetization of zero to the material . When sub jected to a ma gnetic field , the magneti c moments of the domain tend to align with each other. giving a
a. net magnetizat io n to the material. The small arrows in represent momen t s of gro ups of at o m s wh ose exc hange forces (ca used by interactions of spinning electrons in adjacent atoms) have ca used them to become aligned within their domains . Local ized field s ali gn th e moments in a minimum energy co nfiguration . In a.. one such configuration con tains four major local orientations. Lines between domains are referred t o as domain walls . The wall is a region of finit e width where m any moments provide a more or less sm ooth transi ti on between two domain orie ntat ions. as in b. Beca use the atomic moments within th e wall are partially di spla ced , relatively little energy i.s required t o ca use the wall to move .
Domain wall motion in a magnetic wire. In a., the wall is placed in an external magnetic field . H. The effect 1s to ali gn the atomi c moments with the field . Mom ents on the right of the wall move to oppose H, while m o ments on the left try to align them se lves with H. The net re sult is that the wall move s with velocity, v. in th e direction of H. When H exceeds a wall m oti on threshold , Hw. wall ve loci ty is:
v = C(H Hw) where C is a m ate r ia l ve l oc ity co nst a nt , typi cal ly 13,000 cm /s for ea ch Oersted of propagation field . In b.. the domain m o m en ts po int away from t he wall. Wall velocity is sti ll give n by the formula, but is in a direction opp os ite t o H.

~ Write head
(- - - - - -) 0. ~ Nucleati on field
(,..-------- - - )
b.
c.

Domain nucleation. Info rmation m ay be written into a magnetic media by "n ucleating" a 180° reverse d m agneti c domain . Th e wire in a. is initially magnetized on one direction. In b.. the field prod uce d by the write head is grea t er th an the nucleation (switching) field of the wire. Hn . so it nu cleates a reversed magneti c domain . If H is larger than Hw, the wa lls will move apart and th e domain wi ll grow as in c. There are two distinct field s applied : a nu c leation fie ld strong enough t o c reate a domain in the wire . and the m oti on field which is suffic ient to ca use wall motion , but no nucleation . Thu s, the range where domain walls m ove is when Hn > H > Hw. If H is greater than Hn. spuriou s walls are crea ted . Typical val ues of these threshold s are an Hn of 30 Oe . and an Hw of 8 Oe , for fine m agnetic wire.

60

Circle Reader Service #33---+

Here you have two of those chips joined in a 128 word by 2 bit memory component. Access time is still twenty nanoseconds and power con- · sumption is still less than half a milliwatt per bit. Cost is still less than any other memory component in its speed range. We keep the cost down with automated package assembly and automated chip joining. Labor cost is practically nil. The package is ideal for memory products

because of its high lead access per unit area. Thirty-six leads requ ire only four tenths of a square inch. If this module meets your needs, you can get immediate delivery from lntermark Electron ics -or from our factory in Phoenix.
Take twenty of these and what do you get?

M E MORIES COURSE · PART 5

Wr ite ~.~.,,.._.!-.,,--~.-.. co il

Sensing coil

Write head\ l..nJ

Magnetic wire

~CJ~CJ~c::J~CJ~CJ

B A l..nJ

Propagating electrodes

2

Field direction ~

~EJ~o~o~ES~o

lr..J

0T2

)3

::: +----- ,._.__ --+ -+ ,._.__ +- --+ -+

- - - Swi~A SJ ~CJ~CJ~CJ~CJ \r.,J

0 - :: T3

)4

~a~a~a~a~a

' - switch B

b.

Domain motion und er the influence of periodi c forcing f ields. The propagation field can be produced by two insulated, interlaced condu ctors . The co nfiguration in a. supplies Hn via c urren t in the write electrode, suppl ies H via current to the pr opagating electrodes A and B, and detects the flow of domains through the dq,/dt-indu ced vo ltage in the reado ut co il loo ping the magnetic wire .
In b. , Row 1 shows the ini tial con fi gu rati on with the entire wire magnetized to the right . Sma ll arrows indicate the alternating H-field pattern set up by the propagation c urrent. In Row 2, a domain is written into the wire and its. walls move apart under the influence of H until th ey become ··trapped ." The current in A is then reversed. in Row 3. placing the right wall in a field pointing to the left. and the left wall in a field po inting to the right. Under these co ndition s, both walls move to the right until the doma in beco mes trapped again (s table minimum energy position). com pleting the first \f4 cycle . To move the do-
main another co nductor-width , c urrent in Bis reve rsed in Row 4. As before , the leading edge propagates
to inc rease th e domain length and th e tra iling edge to shorten it. retaining domain length during propagation along the wire .
Binary l 's are represented by discrete domains; O's by the absence of domains . Cond ucto rs are dri ven by square wa ve. 2 ph ase drive c urrents. A sho rt time after initiat ion of the prop aga ti on c urrent. the en t ire wire assumes the remn ant magnetic state at the input end. because all domain walls within the wire are forced toward the output.

rate may be varied by changing the propagation pulse rate, leading to synchronous or asynchronous operation. Rates up to 200,000 b/ s are available.
Storage is non-volatile; domains can remain at rest indefinitely. Shifting may occur in either direction , giving first-in-first-out (FIFO) or last-in-first-out (LIFO) operation or any combination.
Reado ut is effectively NDRO. After being read , a bit co ntinues to the end of the magnetic wire . Space between the se nse head and the end of the wire allows data retrieval after a power failure . A reverse shift of one step restores the data byte which was to be read prior to loss of power. Temperature is no problem over the range of 0 to 120°C .
Since data is seriall y accessed , a tradeoff exists bet ween average access time to a word and the length of a band of wire . Band length determines access time, independent of
62

t he total memory size. The capa bilit y to store and dis-

charge data at different rates leads to buffering appli-

ca ti ons.

Other applications include shift registers, recirculation

registers , and flip- fl op registers . The memory is erasable,

making it desirable for security applications . Some types of

memory elements are removabl e and portable . Large

memories are easy to mechanize beca use onl y a single set

of driving circui try, plus appropriate selection switching is

required .

~

INFORMATION RETRIEVAL Com puters and peripherals, Digital design
Circle Reader Service #34- - +

This is a memory system card. It contains the memory address register, decoding, storage sense amplifiers, write amplifiers, output buffers, interleaving capability and all the controls necessary for complete memory function. It is available in word sizes from 128 to 8192 and bit sizes of 1, 2, 4, 8, 9, 10, 12 and 16. Any number of these cards can be wired together to form a larger memory system of any desired word or bit size. Power consumption is less

than one milliwatt per bit. Guaranteed access times are 100 ns, 200 ns or 300 ns. And again, the prices are lower than any other memory cards in the same speed range. And they're available now, either from our Phoenix factory or from lntermark Electronics.
Take seventy-two of these and what do you get?

NOW. ..
a COURSE
on the New technology of optoelectronics
Compiled by the editors of The Electronic Engineer, this is truly the definitive course on OPTOELECTRONICS. It is a practical and tested demonstration which will enable you to master even the most complex assignments, many of which can now be solved for the first time!
The Course is an essential technological contribution to all those involved in the research , design , development and engineering of electronic components, circuits, systems, equipment and services. Completing this Course will enable the engineer to acquire a thorough and professional knowledge of optics and at the same time to qualify as a skilled buyer of optoelectronic components. Some of the subjects covered in the Course are:
The background on Optoelectronics ... Physics of light-as applied to semiconduc-
tors ... Physical definitions of optoelectronic terms .. . Materials-for both sources and detectors .. . Sources - Light-emitting diodes - Materials,
efficiency ... Detectors-Photoconductors (or photoresistors)
photodiodes-Materials, efficiency .. . AmpIifiers-Phototransistors, photoFETS-
Materials, efficiency, sensitivity . . .
The Course also includes many simplified , practical applications for optoelectronic components such as light choppers, modulators, signal isolators, card and paper-tape readers , counters, sorters and detectors.
This complete, authoritative and timely Course in Optoelectronics costs just $4.00 postpaid and includes an examination for those who wish to qual-
ify. All who pass the examination will receive a
Certificate of Completion from The Electronic En gineer. To get your copy simply send check, cash or money order to Course Editor, The Electronic Engineer, One Decker Square, Bala Cynwyd , Pa. 19004.
E-6
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Send me your new Course on Optoelectronics at a cost of $4.00 per copy. Payment is enclosed. Send the Course to me at:

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64

NOW... Hear this
In your own home or office: A one hour discussion on ...
''SELECTING MAIN FRAME MEMORIES''

If you missed the Computer Designer's Conference in Los Angeles, you can still get the latest information available on MAIN FRAME MEMORIES , a topic generating great interest throughout the industry. The 21/2 hour discussion has been tape recorded and edited into 1 hard hour of authoritative, factual information on the state of the art by this panel of industry leaders:
Robert Noyce, President, Intel Corp. Linder Hobbs, President, Hobbs Associates Philip Harding, Memory Systems Development, Electronic Memories Cloyd Marvin, Vice President, Four-Phase Systems, Inc. Edward Schwartz, Advanced Systems Engineering, Lockheed Electronics
The report presents an up-to-date review on the relative cost/performance trade-offs of all main frame memories. In addition , the tape recording answers such questions as: "What does the future hold for plated wire, core, semiconductor and other technologies?" ... "Where are associative memories headed?" .. . " What about volatility and reliability?" . .. " Will memories be marketed more as components or as systems? " . .. "Is price per bit important?" And more.
Why not get your own complete cassette recording of this remarkable session? This report on Main Frame Memories is available nowhere else. Hear it at home, your office or in meetings with business associates.
1-hour cassette recordings may be purchased at $6.00 per copy . To get yours, fill out the order form and mail with your check or money order to The Electronic Engineer at One Decker Square , Bala-Cynwyd , Pa. 19004.
Because this is a limited edition, we suggest
that you order now while tapes are available.
E-6

Enclosed is my check or money order for

$

for

tape recording{s) at a cost

of $6.00 each. Send as soon as possible to:

Address ______Company ______
City_______State ____ Zip _ __ E-6
THE ELECTRONIC ENGINEER · June 1971

This is a 125 ns access time 32K Byte memory system. But it can be built to any desired word size or bit length with very little effort. If 125 ns access time isn't needed for your system , we can save you money with a 225 ns or 325 ns version. At any of the three speeds, you 'll find our price is lower than any other equivalent memory system. And you'll also find that we consume less than half the power of any system of equ ivalent speed. We can supply these systems with a customized interface to meet your

specific needs. And we offer a single bit error correction and double bit error detection option , a re-try option, a failed card reporting option, a self-test option, a cooling option and a power supply option. The inherent high reli abil ity of semiconductor products combined with the utilization of error correction and detection systems, re-try and a failed card reporting system make unscheduled interruption a thing of the past. All systems are field expandable to 131K Bytes. Okay. Now if you 've read the three preceding right hand pages , then you know about our low-cost, high-speed chip. Which goes into our low-cost,

high-speed pak. Which goes into our low-cost, high-speed card. Which goes into our low-cost, high-speed system. So let's talk. For more information call or write our main office in Phoenix or phone our nearest regional sales office: Boston (617) 227-4444 ; Chicago (312) 529-7019; Los Angeles (213) 672-1400 ; New York (212) 288-8429; Ph iladelphia (609) 234-0185; San Francisco (415) 592-8137.
An affiliate of Electronic Memories & Magnetics Corporation 3883 No. 28th Ave., Phoenix, Ar~ . 85017 . Ph one (602)2 63-0202
semiconductor electronic memories, inc.
International Semico nductor Cor p. France, 20 Rue Gambetta, Paris 92 Boulonge, Fra n ce Phon e 825 ·9 5 ·55

HP's got a great new idea in counters: buy one that just fits your specific application- without paying for extras you'll never use. Yet make your.choice from a family of six counters with a wide range of unique features, at prices so low you'll wonder how we did it.
You'll get all the things you expect from our 5326 and 5327 family of counters: totalizing, frequency, ratio, period and time interval measurements, in a range of 50 MHz or 550 MHz.

In addition, they let you perform tasks no counters could handle before.
For instance, you can now do IC logic timing testing simply and economically with 15 picosecond resolution. HP's unique time interval averaging mode makes it possible! (Request HP Application Note 129 for the story.) Price is just $1195 for a 50 MHz unit and $1795 for the 550 MHz model with this powerful time interval capability.

·

For just $355 more you can get a counter

with a DVM built in. So you can do things like

measure rise times more rapidly, simply and

accurately than with a scope. And you can check

external de voltages with it, too. Add a $60 HP

11096A Probe if you need rf voltage measurements.

Want programming capability? Our options

will permit remote control of all front panel

functions, including trigger levels and attenuators.

II I t ..
·i I.·i

Computer interface is easy and costs less than ever.

·
Suppose you just want the basics? Our frill-free models will supply them with troublefree, simple operation. They'll cost you $950 for 50 MHz, $1495 for 550 MHz.
Your HP field engineer has the 5326/27 data sheet that tells the complete story about these precise new counters. Or write to HewlettPackard, Palo Alto, California 94304; Europe: 1217 Meyrin-Geneva, Switzerland.
02102

i:IJ HEWLETT PACKARD
Counters that promise a lot and deliver it all.
Circle Reader Service #36

POWERTEC
WINS
POWER RJICE With Retard LowPriiesForNew, High Performanie OEM Series

JILL MODELS DELIVERJIBLE FROM STOCK IN 14 HOURS

Leading the power supply industry with new low prices, top performance and reliability, Powertec's new OEM Series offers 7 popular voltages, in six basic sizes, with 42 power output combinations and is main frame, peripheral and instrument rated.

Available from stock, the OEM Series is a "no frills" fundamental new design - not a price cut, loss leader! Don't take a chance on an also-ran! Get a winner from THE power people at THE power house - Powertec. Request free application data and catalog.

Model Number

*(5)

sv

6V

*(15)

*(24)

Unit Price

12V

lSV

18V

20V

24V

2B(*)

3A

2.SA

l.SA

l.3A

1.0A

1.0A

1.0A

$24.95

2C(*)

6A

SA

3.0A

2.8 A

2.0A

2.3A

2.3A

$44.00

2D(*)

12A

lOA

6.SA

6.0A

4.SA

5.0A

5.0A

$75 .00

2E(*)

25A

23A

lSA

l4A

lOA

12A

llA

$129.00

2F(*)

SOA

46A

30A

28A

20A

24A

22A

$219.00

2G(*)

75A

68A

45A

42A

30A

36A

33A

$299.00

· REGULATION: Line± .05%, Load± .05% · INPUT: 115 VAC ± lOV 47-63Hz · RIPPLE: lmv RMS (5 & 15V), 3mv RMS (24V)

· O.L. PROTECTION: Current limit/foldback · RESPONSE: 50µ.sec typical · TEMPERATURE: 0° C to 40° C derated to 71 ° C

PO\NERTEC INC. anAirtronicssubsidiary
9168 De Soto Ave., Chatsworth, California 91311 (213) 882-0004 TWX 910-494-2092

68

Circle Reader Service #37

THE ELECTRONIC ENGINEER · June 1971

G

THIS MONTH'S IDEAS

PAGE

Zero crossing detector uses logic gates ............ ........................... .............. ... .. ....... ..... .. ..... .70 Sinusoidal frequency halving ............... ... .. .. ........ ... ...... ...... ... ...... ...... ............. ... ................ .70 Frequency divider from a clocked R-S f li pflop ........ ................... ........ ... ........ ... ... ... .... ........72 Speed up your precision rectifier .. ... .... ..... .. .... .................................. .. ....... ..... .... .... ...... .....72

VOTE for the one you like best
Wr ite the number of the Idea you like best in the box on the inquiry ca rd and send it to us .
SEND us practica l. reproducible ideas that are origina l with you and have been implemented with linear or digital ICs . If we publish yo ur idea . you win a check for $25 .00. If our readers vote yours the best of the issue in which it appears. yo u have your choice of a Simpson 270 or Triplett 602 multitester. After 12 issues . our readers will vo te on the best idea for all 12 issues . The winner gets his choice of either a Hewlett-Packard 1206A or a Tektronix 5103 N osci llosco pe.
Submit your IC Ideas to : Alberto Socolovsky. Ed ito r THE ELECTRONIC ENGINEER Chestnut & 56th Sts . Philadelphia . Pa . 19139
HOW YOU VOTED
In o ur January iss ue. we published our IC Idea winners for the year. and as ked you to select "the best of the best. " Wei I, the ballot s are in and have been tabulated . and we have a winner . Selected as the best IC Idea of the year was "Zero-beat detector" by Tim K. Aa ltonen.
Th e c ircuit. as you may remember , is a simple and inexpensive way to adjust two frequen c ies t o within several Hertz of each other .
.Mr . Aaltonen. our prize-winning author , is a co nsultin g enginee r in New Roche ll e, N.Y . As his prize. he ha s selected the Tektr oni x 5103N sco pe .

THE ELECTRONIC ENGINEER · June 1971

69

G

Zero crossing detector uses logic gates
Stuart Culp , Gene ral Electric Co .. Uti ca. N.Y.

It is often necessa ry in digital systems to detect zero crossing or to generate timing signals from an ac source . And in m os t of these applications, special power supply voltages are not available. In thi s case, a sy nc signal for a TV system was to be provided from a 400 H z power supply.
Resistors R ,, R ,, R J and th e internal pull up res istor of G 1 bias G 1 in a quasi-
c , lin ear mode, Capacito r turns this network
int o a low pass filter which rej ects signals above 400 Hz in this particul a r des ig n . The 20 V pk -to- pk input signal is provided by a n ext ra winding o n the
c , power transformer. Gate sharpen s the
co rn ers of the squ a red sig nal , a nd a lo ng with R 4 provides positive feedback to th e input of G1- an esse ntial fea ture to eliminate hash or oscillations at zero crossover. Gate G2also acts as a n output buffer.

II
20 V P-P ! 20% 400 Hz AC

To vote for this IC Idea , circle 975 on the Reader Service Card

R1 100().0.

R2 1000.0.

c,
22J-LF

R3 1000.0.

-=

DTL-932

8
Output

7

14

+ 5VDC

Sinusoidal frequency halving
Marv in K. Vander Kooi , Fai rc hi ld Semico nduct or . Mountai n View. Ca lif.

-t 15V

ISpF

M ost frequency halving circuits use dig ita l techniques which destroy th e si nusoidal nature of th e input waveform . If yo u need a sine wave output, yo u mu st rebuild it with di ode shapi ng networks or fi lters. This circ uit preserves th e sinusoidal rate of change of the waveform and gives yo u a si ne wave output at o ne half the input fr eq uency .
The µ,A 795 and th e two hal ves of th e µ,A 747 form a standard square root circ uit. The o utput fr o m this circuit is t he posit ive sq uare root of the absolute value of the input voltage . Since the square root of the absolute
va lue of 0.5 -0.5 cos wt is equal to th e a bsolute va lue o f cos 1/ 2 wt , the o nl y remaining problem is to eliminate th e absolute value feature. The inverter for a ltern a te lobes is an op amp used alternatel y as a vo ltage follower a nd a xi inverter under co ntrol of FF1.
Th e FETS Q 1and Q, d o the actual analog
swi tching of the inputs to the amplifier.

Y-Offs e1 adj . 22µF

1Kn 1Kn

IOKn

IJ.A79 5

-15V

13 6.8 Kn

3 l 4l - - -- ----4---=-

4 .7 K n

7.5Kn

~
5Kn

5Kn

t +.s0v ~
Vi n
-. sv
-I V IOKn

IOOKn

10

l-..l.l...- - - - - - - - - - - - - - - - + - . , , , . , . - - o vin;-.5 - .5 Cos (w)

IOO Kn

IOOKn

SKn
Potenti ometer R 1 sets the precise trigger point of the flipfl op by set tin g the voltage reference. to th e

+IVfv- SIKn

-15V

f

Vo 0

-IV
comparat or. The output wave fo rm is a I V peak sinusoid a t exactl y one ha lf the input frequen cy.

To vote for this IC Idea, circle 976 on the Reader Service Card

70

THE EL ECTRONI C ENGINEER · June 1971

MACRO DATA OFFERS
'OALIPplNG''
1's & O's FOR SEMICONDUCTOR
MEMORIES ...
OR YOU CAN GENERATE
{)
YOUR OWN WORST CASE PATIERNS.
With our MDIOO semiconductor memory tester, walking l's and O's are furnished
as part of the package .. . in fact, they've been improved to the point that
we now call them "galloping" l's and O's. Try them on your favorite memory.
Macrodata has available a library of test routines tailored specifically for
semiconductor memories.
If your memory falls within 1 word by 1 bit, or up to 65,536 words by 16 bits the MDIOO has everything you
need to test it, be it RAM, ROM or Shift Register, in chips, packages, memory card sub-systems, or final
systems form.
We provide, and take full responsibility for, the "Personality Cards" to test each specific memory and their matching firmware. Up to 5mHZ continuous rep rate (200NS cycle time) and down to IONS memory access time can be resolved. All systems variables, in any combination (min, nominal, max - through millions of patterns) can be run sequentially and continuously in any order.
The MDlOO is a complete semiconductor memory system exerciser priced at $13,750.00 with your choice of 2 standard Personality Cards.
Circle the reader number below for complete technical specifications. For faster service call the main plant (213) 882-8880.
.(..
Macrodata Company o(
g Test Systems Division o
20440 Corisco Street Chatsworth, California (
91311 ~

THE ELECTRONIC ENGINEER · June 1971

Circle Reader Service #38

71

G

Frequency divider from a clocked R·S flipflop

Jozef Sabo l , Technical Universi ty of Prague . Prague . Czechoslova kia

Yo u can use this impro ved toggle m ode fl ipfl o p as a fr equency di vider ove r a wide ran ge of fr equen cies a nd pul se

i ,.-.
,.----4

r12-0-0..p..F-----

470.0.
--J>.,A/'.,. -

-

-

-

-

-

1

' C1 :

R1

:

~±--

:

!

width s . U nlik e th e sta nd a rd cloc ked R-s

s

fl ipfl o p (solid lines), this m odifi ed

ve rsio n (dashed lines) cann ot go to a n indetermina te sta te, The feedbac k fr o m

r -·- c

integ rati ng network s R 1C 1 a nd R 1C2

ca uses suffi c ient delay to ensure

R

th at the outputs of both G , and G2

ca nn ot be low at the sa me tim e. This holds
t rue as long as T < 0.6 R C, where Ti s

Cz ,~, 200 pF Rz

the width of the input pulse a nd R C

I
--~-

is the tim e co nstant of th e integ ratin g net wo rks. The circuit can also be trigge red fr o m pulses hav ing a rbit ra ry width as long as the tim e co nsta nt R in C in is less th a n th e R C tim e co nst a nt. Yo u will fi nd th a t th e circui t o pe rates reliably at rates up to severa l MH z.

L---- -- - -r - ---~-c-.m-:,nI -- -< In pu t

1

i IOOpF

I

I

I
470.0, ~ Rin ~

I
;~ IN3 193
;

I

I

I

I

1

:

:

I

To vote for this IC Idea , circle 977 on the Reader Service Card -~-

-~

u Gate I --,u1. . . - - - - - - - . - - - - -
----u.------u- Gote3

Speed up your precision rectifier

Allen Cole , Avionic and Digital Equipment ltd .. Midl othian . Scotland.

If yo u have occas ion to desig n a precision

rect ifi er, d o n' t fo rget th at o ld sta ndby,

the 709 o p a mp . The circuit shown here

ta kes ad va nt age of th e 709's progra mm ab le

fre qu e ncy co mpensati on to g ive a fas t slew rate in the " dead zo ne " of wha t is oth erwise

Input

IKU

a co nve nt io na l precisio n rect ifie r.

As th e inpu t vo ltage crosses 0 V, th e
o utput swings betwee n + Vr a nd - Vr , where

500.0,

Vr is th e fo rwa rd vo ltage d ro p of th e

diodes. When this happe ns, th e o p amp is

effec tively open loo p, a nd th e detec ti o n

thres hold is a bout J1f / A ·. (A . is th e open loop vo ltage gai n of th e o p a mp). If R r = R i, the freque ncy co mpe nsation must be

Input ----1\f\--

fo r 0 dB gain . With this co mpensati o n, the accur acy of the rec tifier is co nside rabl y

Output _J'\__J'\___

redu ced a bo ve a bo ut I0 kH z beca use th e o pen

loop gain is low, a nd m o re impo rt a ntl y,

th e slew ra te is a lso low.

This circuit overco mes the limitatio n

by cha nging the co mpen sati o n to imp rove

th e perfo rm a nce in the o pe n loo p dead

zo ne. T he output co mpensati o n ca pac ito r fo r 0 dB operati o n is co nn ec ted to th e

operat io n po rt io n of th e cycle, when o ne o f the d iodes is fo rwa rd biased , th e

feedb ac k resisto r side of the d iode. The

co mpensati on ca pac itor co nsists of 3 pF

mi ni m um a ll owa ble va lue, 3 pF, is bet wee n pin 6 a nd pin 5. In th e no rm a l

a nd one o f th e 200 pF' s in para ll el. This gives th e co rrec t va lue fo r 0 dB operati on.

To vote for th is IC Idea, circle 978 on th e Reader Service Card

IK.O.

Output

200 pF

3 pF

200 pF
I K.0.
®

In th e open loop por tio n of th e cycle, th e co mpensati o n ca paci to r is 3 pF . This simple addit io n to the ci rcui t ex tends its use fuln ess, es pec ia ll y a t low levels, fr o m 10 kH z to a bo ut 50 kH z.

72

T HE EL ECTRONIC ENGI NEER · J une 19 71

AND NOW "Q" CORE ... THE FIRST MAJOR ADVANCEMENT IN MAGNETIC ROM SINCE 1952!
... THE UNIQUE NEW PROPRIETARY "Q" CORE represents the ultimate in reliability. It eliminates the inherent mechanical and electrical weaknesses of the " U" and "E" Cores. WHY IS "Q" CORE UNIQUE? · Quick change, pluggable matrix. How fast can you move? · Yes, it can be altered in the field faster than any other system! · Need a system than can drive a complete library of programs? · The 13" x 11 " card holds up to 100,000 bits with cycle times of 200 nanoseconds! And , one of the really outstanding features is the off-the-shelf delivery schedule.
Call or write today:

THE ELECTRONIC ENGINEER · June 1971

Circle Reader Service #39

73

,,

74

THE ELECTRONIC ENGINEER · June 1971

NON

Analog multipliers for the economy-minded

Analog multipliers have long been attractive to circuit designers for a wide varie ty of ap plications. The one feature wh ich has held back thei r application in many cases has been their relatively high cost. Recently, however, two firms have introduced variable transconductance-type multipliers, which are aimed at opening new markets by virtue of their lo w price tags .
The AD530 from Analog Devices has the distinction of being the first complete monolithic multiplier to hit the market. While previous IC units required an external op amp in the feedback loop, the only outboard components used with the AD530 are some trimming potentiometers to set gain and offsets.
You can get the device in two versions, the 530J with 2% of full scale accuracy, and the S30K which has a 1% accuracy spec. Both versions have ±IO Y, S mA output, I-MHz small signal

ba ndwidth , 750-k H z full power response, 4S-Y / µs slew rate a nd a minimum 7-Mn input resistance.
In 100 piece lots , the AD530J is $20 eac h, while the 530 K is $30. Analog Devices, Route I Industrial Park, Norwood, Mass. 02062.
The second new multiplier on the market is the M4 l 6 from lnt ro ni cs. Comparing the M416 with the AD530 illustrates the discrete vs monolithic approach to circuit design . With the M416, lntronics is able to hold the tolerances a little tighter for better accuracy, but it costs money to d o it. The M416 gives you a gua ranteed overall accuracy of 0.5 % of full scale, but. it cos ts $6S each in 1-9 quantities. While this is lower than most other discrete multipliers, you will have to trade off accuracy vs price according to yo ur application. Some other specs of interest include a 6-Y/ µs slew rate, a bandwidth of 7SO kHz and full power bandwidt h of

100 kHz. The output is also ± 10 Y, 5
mA . lnt ro nics Inc., S7 C h ape l St. , Newto n, M ass. 02 158.
For more information on the AD530 Circle Reader Service #275
For more information on the M4 l6 Circle Reader Service #276

LIQUID CRYSTAL DISPLAYS This display consists of a thin layer of
normally transparent liquid crystal ma-

DIGITAL MULTIPLEXER
Dijitscan 2000 is a compact, digital sca nner that accepts multiple BCD input s a nd provides them sequentiall y at the output. Pivan Data Systems, Inc., 69S5 N. Hamlin Ave., Linco lnwood, Ill. 6064S.
Circle Reader Service #279

SILICON DIODE RECTIFIERS
New 12 A encaps ul a ted silicon diodes are roughl y 1/2 the cost of equivalent-

terial between two electrodes. When an electric field is applied , the material becomes turbulent, reOecting and scattering amb . light. Optel Corp ., Box 22 15, Princeton , N .J . 08S40.
Circle Reader Service #277
GLASS DELAY LINE Model !024 digital delay line is I0 .24
µs long a nd operates at I00 MHz. Only 2 Vs x % x 5,1s in . It can be used as a ~ omput e r memory storing 1024 bits . About $0 .0 S/ bit in 1000- piece quan . ls omet Co rp., 103 Bauer Dr. , Oakland , N .J . 07436 .
Circle Reader Service #278

SENSOR ASSE MB LY These optical pairs are a combination
of two thi~e a<rny '°"-
..· .....
tains gallium arsenide LEDs; the other one of several types of phototransistors. Less than $3.00/ pr. in quan. HE! , Inc., Jonathan Industrial Ctr. , Chaska, Minn . SS3 18.
Circle Reader Service #280

rated stud type devices. The 6QD series units are availab le in seve n peak inverse voltage ratings fr on:i SO to 1000 Y. Sarkes Tarzian , Inc., 41S N . College Ave ., Bl oomington , Ind . 47401.
Circle Reader Service #281
CASSETTE COPIER
This portable high-speed cassette copier duplicates the contents of a master casse tte once eve ry 2 1/ 2 min. Model 52 1 resembles an attache case and can copy from I to SO cassettes. M CA Technology Inc., l 303S Saticoy St. , N o. H ollywood, Calif. 9160S .
Circle Reader Service #282

THE ELECTRONIC ENGINEER · June 1971

75

For quick information use the reader service card inside the back cover.

ILLUMINATED SWITCHES
11 ~
Desig ned for rear panel mounting , these push-button switches mount in a 3/s in . hole . They are available with either neon (Series 913) or incandescent lamps (Series 922). Dialight Corp. , 60 Stewart Ave ., Brookl yn, N .Y. 11237 .
Circle Reader Service #283
MAGNET WIRE New precision wrapped magnet wire
is for applications in high reliability ci rcuitry . It uses a 32 A WG silver plated conductor wrapped with Kapton . The oo is held to 0.0155 ±0.001 in. Connecta Data , Inc., Box 355 , Eatontown, N .J . 07724 .
Circle Reader Service #284
DC TACHOMETERS These two new tachometers are both
brush type units having high linearity, 0.1 %. They are temperature compensated to 0.0 I%/°C from - 25 ° to
+ 175°C. Harowe Servo Cont ro ls, Inc.,
Westt own Rd. at West Chester Pike, West Chester, Pa . (21 5) 692-2700.
Circle Reader Service #285
FET OP AMP
Model 163A FET op amp has a de ga in of I00,000, full power response of I00 kHz, and a 6 V/ µs slew ra te. Dynamic Measurements Corp. , 6 Lowell Ave. , Winchester, Mass. 01890.
Circle Reader Service #286
FIBER OPTIC SCA NNER

CERA MI C CAPAC ITOR Mono- Kap 50, 100 and 200 Vdc ca-
pacitors come in six sizes (0 . 100 x 0. 100; 0. 150 x 0.150; 0.200 x 0.200; 0.300 x 0.300, 0.400 x 0.400 and 0.500 x 0.500) and four dielectrics: NPO, N , Z5U, and general purpose. USCC/ Centralab, 2151 N . Lincoln St. , Burbank , Calif. 91504.
Circle Reader Service #288
FLATTED TOGGLE SW ITCHES These miniature toggle switches with
flatted handles have a current rating of 5 A at 115 Vac. Prices start at $2 . 15 ea . (SPDT) and $2.65 ea. (DPDT) in si ngle lots . Alcoswitch , Box 1348, Lawrence, Mass. 01842.
Circle Reader Service #289
POWER TRANSISTORS PT-5501 series transistors, have t11rn-
off times of < 700 ns at 50 A, VCE(sat) of < 0.5 V at 50 A and guaranteed hFE at 100 A. PowerTech , Inc., 9 Baker Court, C lifton , N .J . 07011. (201) 4786205 .
Circle Reader Service #290
CRYSTAL OSCILLATOR
M odel CQ plug-in oscillator provides a precise frequency or time base for counters or other instruments. Output frequencies available from it extend from 40 Hz through 15 MH z, at accuracies to 0.005 % (50 ppm). Fork Standards , Inc. , 205 Main St. , West Chicago, Ill. 60185 (312) 23 1-3511.
Circle Reader Service #291

POWER DETECTOR Model 3020 is an rf directional power
detector for monitoring tran smitter output in the vhf and uhf communication bands. Complete coverage is offered in the freq . range of 108-400 MHz with a power rating of either 50 or 150 W . Coaxial Dynamics, Inc., 13100 Enterprise Ave. , C leveland , Ohio 44135. (216) 267-2233.
Circle Reader Service #294 LOW-POWER DISPLAY
MAN 4 is a 7-segment ss unit that provides a visible display with inputs as low as 1 mA and 1.65 V. $7.50 ca . ( 1,000 quan .). Monsanto Electroni c Special Products, 10131 Bubb Rd ., Cupertino, Calif. 95014. (408) 257-2140.
Circle Reader Service #295 MICA PAPER CAPAC ITOR
The CEM is a reco nstituted mica paper capacitor that is encased in molded epoxy for critical operating environments. It weighs about 40 g/ in. 3· Custom Electronics , Inc ., EE- 18, Browne St. , Oneonta, N.Y . 13820 .
Circle Reader Service #296
SELF-DECODING READOUT The Major-64 accepts directly any
four, five or six line binary code signal and rapidly selects and projects any one of 64 images on an integral screen : Maj or Data Corp., 891 W . 18th St. , Costa Mesa, Calif. 92627 .
Circle Reader Service #297
POWER THYRISTOR SCR's

This fiber optic "Nano-Skanner" can detect a mark as small as 0.00 1 in . in dia . In field tests it has obtai ned re- , peatability of object position to 0.000005 in . Skan-A-Matic, P .O . Drawer 68, Skaneateles, N.Y . 13152 . (315) 685-3473 .
Circle Reader Service #287

R eed switch. The Rl-12 / 01 o ffer s a combi nation of extreme uniformity, hi gh reli a bility a nd ma ximum economy. Ampere x Electroni c Corp. , Hicksville, N .Y.
Circle Reader Service #292
Thumbwhee/ switches. Decimal point s on 1776 series switches and o n spacers of ot her series are now lighted. Electronic Engineering Co. of Calif., Santa Ana , Ca lif.
Circle Reader Service #293

,rr

11 \
I'

if

These new unil a teral powe r th y risto r SC RS have load current ratings from 0.8 to 35 A and voltage rati ngs from 30 to 800 V. G a te se nsiti vities ra nge from 110 mA to 1-25 mA. ECC Corp. , Box 669, 1011 Pame la Dr ., Eu less, T ex. 76039. (817) 267- 1601.
Circle Reader Service #298

76

THE ELECTRONI C ENGINEER · Jun e 1971

1

· ·

@ @

0
0

·

·····

·
0

· r r r rr

0 0 000

COMPUTER CC:S... LABS
GR!!NS80RO, N . C .
LAB 210

0 1 1 1 1 , 7 O F F · ,
RANGE

~+ 4f

DISPLAY T IME
0

..0 POWI! ..

-SAMPLING-
. 2M"1Z lOOtiZ E:XT

· · ·

INPUT

POO

NOG

w
I

·OV """

.·.··· ···· -·.·. NORM

MAX "''"

MEMORY
STORE l'teAO

"'~en

TEST

ANAl..OG INPU T
a.NCOO!: INPUT

Measure pulse heights with a DVM instead of a scope? Now you can with the new LAB 210 TRANSIVERTER. It's a 10-bit AI D (en coding rates to 2 MHz) with a Nixie tube display showing four significant digits, ± sign , and over-range indication. That 's 10 times scope accuracy ... and a lot more readability!
If you need a memory, too, you can have 100 words on an optional plug-in module . Or maybe you 'd rather plug in an optional tran sient detector for maximum or minimum de-

tection-and-hold. And if you need an analog output, you can have an optional D/ A module , too.
That gives you five precision instruments in one: · AI D converter · ac DVM · 100-word memory · Transient detector for max/min · DIA converter
Check for more information on this totally new measuring instrument.

COMPUTER L ABS .. ~~-

1109 South Chapman Street I Greensboro , North Carolina 27403 / (919) 292·6427 / TWX 510 922-7954

T HE ELECTRO NIC ENGINEER · June 1971

Circle Reader Service #4 1

77

For quick information use the reader service card inside the back cover.

HIGH VOLTAGE DIVIDERS
\-.I
Thick film multi-megohm , tapped resistors on flat substrates offer advantages in hv circuits. Close tracking of individual elements is obtained amo ng resistors differin g in va lue by factors of as much as several thousand. Airco Speer Electronics, Packard Rd . at 47th St. , Niagara Falls, N .Y. 14302. (7 16) 285-9381.
Circle Reader Service #299
DC POWER SUP PLI ES
Three encapsulated supplies, Model s
906 , 903 , and 905, provide ± 5 V o utput
at 250, 500, and 1000 mA , respectively. Used to excite monolithic IC logic circu its, they o pera te from a nom. 11 5 Vac at 50 to 400 Hz. No. 906 is $38.00; No. 903 is $47.00; No. 905 is $66.00. Analog Devices , Inc., 221 Fifth St., ·cam bridge Mass. 02142. (617) 492-6000.
Circle Reader Service #300
PC PA CKAG ING CO NCEPT
Multiflex packaging co ncept combines the techniques of multilayer and flexible ci rcuit constru cti o n, resulting in PCS that ca n be made to bend or twist at any location . Lockheed Electronics Co ., Inc., Data Products Div., 6201 E. Ran dolph St., Los Angeles, Calif. 90040.
Circle Reader Service #301
PUSHBUTTO N SWITCHES
These miniature switches are availab le in std ., watertight an d round base models. The std. and watertight switches a re rated a t 5 A, 125 Vac an d 28 Vdc, res. load. The round base switch is rated at 3 A, 125 Vac and 28 Vdc, res. load. Cutler-Hammer, Inc., 4201 N . 27th St., Milwaukee, Wisc. 53216.
Circle Reader Service #302
ISOLATOR
Optically coupled isolator (SSC-600) has a neon bulb, dropping resistor and Si photocell that operates from 11 5 Vac line . Output current is 200 µA. $4 .00 ea. (I 00 quan .). Solar Systems, Inc., 8124 N . Central Park , Skokie, Ill. 60076 .
Circle Reader Service #303
78

FLAT FLEXIBLE CABLE
Signaflo® transmission cables offer all the advantages of flat , flexible cable and provide closely controlled characteristic impedance, propagation velocity, cross talk and atte nuati on. FlexStrip® ca bles offer easy, economical replacements for individual ro und wires in a wide range of current carrying applications. Ansley Corp., Old Easton Rd ., Doylestown, Pa. 18901.
Circle Reader Service #304

ALUMINIZED ALLOYS Aluminized Kova r® and Westra 42
sealing alloys are for chemical etching or stamping of 1c lead frames . The alloys are available in sheet and strip, fully coated or striped . Westinghouse Electric Corp., Westinghouse Bldg., Pittsburgh , Pa . 15222.
Circle Reader Service #309
OPEN-FRAME REED RELAY

HIGH VOLTAGE SCRs
New C602 high power semiconductor is designed for phase control of hv de motors and replacement of ac contactors in higher voltage ac lines. Rated at 2600 V and 600 A average, it is ho used in a rugged pressure mounted Press Pak featuring I-in. creepage. General Electric, Electronics Park , Mail Drop 49, Syracuse, N.Y. 13201.
Circle Reader Service #305
NEON PILOT ASSEMBLIE S
) ~r
/ ,,
Miniature assembly mounts in a \4 in. hole . The BNM -2R pilot includes a built-in series resistor for 120 Vac operation . $0.59 ea . (IOOO units) . Alcolite Div ., Alco Electronic Products Inc ., Box 134 8, Lawrence , Mass . 01842. (617) 686-3887.
Circle Reader Service #306
DC -DC CO NVERTER PWR-101 converter accepts a 24 V
input and provides a 200 V output. Desig ned fo r use with neon-type indicators, it has many other applications . General Dynamics, Electro Dynamic Div ., Box 2566, Orlando, Fla. 32802.
Circle Reader Service #307
AC SWITCHES Long life (over 500,000 operations)
series 780000 miniature, momentary action , plunger type switches are for use in home appliances, computer hardware cab inetry a nd comm uni cations equipment. Littlefuse, Inc., 800 E. Northwest Hwy, Des Plaines, Ill. 60016 .
Circle Reader Service #308

Overall size of the Series 240 is only 0.20 h x 0.25 w x 0.77 I, with pins brought out on the std . 0. 1 x 0.7 in . pattern for PC board mounting . It is useful for computer applications. Self-Organizing Systems, Inc., Box 9918 , Dallas , Tex . 752 14. (214) 276-948 7.
Circle Reader Service #3 10
PRECISION OSCILLATORS
These variab le frequency oscillator subassemblies are useful in ssB transceivers, spectrum analyze rs , selective voltmeters and specia lized test equipments . Standard models include freq . ranges between 2.5 MH z to 6.0 MH z. TRW Inc., Davis & Copewood Sts., Camden, N .J . 08103 . (609) 465-5 500.
Circle Reader Service #3 11
TRANSISTOR SOCKET
This 1/4-turn Teflon , T0-18 transistor soc ket , fe at uring fo ur angled leads (three active, and one passive-serving as a convenient dummy tie-point lead), mounts in an unchamfered punched "D" hole for improved pullout resistance. Overall dimensions of socket No. 027-1706 are 0 .28 1 in dia . and it' s 0.430 in . long. Sealectro Corp ., 225 Hoyt St. , Mamaroneck , N .Y . 10543 .
Circle Reader Service #3 12
LIGHT EMITTING DICE
These PD5033 gallium phosphide di ce have an emission at 570 nm and a typ. light output of 300 ft-L at 10 mA . The 25-m il sq. dice are suitable for use in indicator lamps and custom design film arrays and readouts . Ferranti Electric, Inc., E. Bethpage Rd ., Plainview, N .Y . 11803 .
Circle Reader Service #313

THE ELECTRONIC ENGINEER · June 1971

CENTRALAB SEMICONDUCTOR
Division · GLOBE-UNION INC. 4501 NORTH ARDEN DRIVE EL MONTE . CALIFORNIA 91734

THE ELECTRONIC ENGINEER · June 1971

Circle Reader Service #43

79

TERMINAL JUNCTION SYSTEM

BREADBOARDING STRIP

MINIATURE CO NNECTO RS

Qualified to Mi°l-T-81714A, these terminal j un ction systems have environmental "insert" modules that lock into tracks for use in high reliability and extreme environmental applications. Viking Indu stries, Inc., 21001 Nordhoff St., Chatsworth , Calif. 91311.
Circle Reader Service #31 4
SUBSTRATES CONNECTOR

With Super-strip, components are easily inserted and securely held by pressure; no soldering is needed. Components are reclaimable, and the strip is reusable. $18.00 (l-9). AP Inc. , 72 Corwin Dr. , Painesville , Ohio 44077. (216) 357-5597.
Circle Reader Service #31 8
MULTI-PIN CONNECTOR

These D-subminiature rack and panel co nnectors co me with 0.025 in .' so lderless wrap tails . They are available in 9, 15 , 25, 37 an d 50 con tact sizes . Cinch Mfg. Co. , a division of TRW Inc ., 1501 Morse Ave. , Elk Grove Village, Ill. 60007 .
Circle Reader Service #322
FLAT CABLE CO NNECTOR

Designed to accept 0.040 in. thick single-sided ceramic substrates, the basic edge-mount co nnector is avai lable in the popular 40-position configuration with contacts on 0.050 in . centers . AMP In co rp orated, Harrisburg, Pa . 17 105.
Circle Reader Service #3 15

New connector can handle 20-gauge wire and up to 85 contacts. Four sizes are available: shell sizes 9, 12, 15, and 18 containing 13, 31, 55, and 85 contacts respectively. Microdot Inc., 220 Pasaden a Ave., South Pasadena, Cali f.
Circle Reader Service #3 19

With the new Tapecon TM co nnector you just place the cable between connector halves and tighten two screws to skive the insulation and make electrical contact with the conductors. Burndy Corp ., Norwalk , Conn. 06852 .
Circle Reader Service #323

30 CO NTACT CO NN ECTOR

SOLDERLESS WRAP BOARDS

INTERCONNECTION SYSTEM

' ~,.... l .: : ~
This female con nector accepts a 30 contact male PC header, or two 15 con-

Two new general purpose boards let yo u mix 14-, 16-, 24-, and 36-pin IC sockets in any desired arrangement. The boards contain all holes for mounting, but are provided without sockets. They are consistent with the format of th e company's 715 line of cards. Cambridge Thermionic Corp., 445 Concord Ave ., Cambridge, Mass . 02138 .
Circle Reader Service #320

These miniature modules (Mil-T81714 type) are for PC board or black box mounting. They provide 1/ 0 source including internal con tact bussing to suit your applications. Appleton Elec-

tact PC headers. This approach allows either individua l or multiple PCB con-

LSI SOCKET

tric Co ., 1701 Wellington Ave., Chicago, Ill . 6065 7.

nection . Contact spacing is 0.156 in.

This dual in-line socket accepts 40

Circle Reader Service #324

Connector Operati on, Control Data lead 1cs with 0.600 in . between rows .

Corp. , 31829 La Tienda Rd ., Westlake,
Calif. 9136 l. (213) 889-3535. Circle Reader Service #3 16

Solder pocket, PC or solderless wrap termination. Insulator is glass filled nylon with pol arization notch and mounting holes. Socket height above the

DIP SOCKETS Preci sion series of 14- and 16-pin
universa l DIL sockets for automatic sol-

PCB edge connec tors. These connectors have 15 /64 in. long dip solder tail s for through connecti on of multiple board la ye rs. Cinch Mfg. Co., Elk Grove Vil-

board is 0.3 10 in. max. $3 .55 to $1 .31 . Augat Inc., 33 Perry Ave., Attleboro, Mass . 02703. (617) 222-2202.
Circle Reader Service #321

derless wrapping feature closed entry contacts wi th a large positive a rea of contact sur face. The low profile Series 41000 has front removable contacts. Dynatec h Corp., 1225 E. Wakeham

'

lage, Ill. Circle Reader Service #31 7

Interested in connectors? See "They ve got connections" on p. 29.

Ave ., Santa Ana , Calif. 92702 . Circle Reader Service #325

80

THE ELECTRONIC ENGINEER · June 1971

LOW POWER TTL CRaM COURSE.

Low power TTL isn't exactly a household word yet among design engineers. So we'd like to offer a quick summary of low power TTL. What it is. Who uses it. Why. Why not. Plus, a list of our products.
After reading this page, you'll probably decide to specify low power for your next system. (If not, you'll at least have lots of cocktail party material.)
PART ONE: A DEFINITION
Low power TTL is an offshoot of the 54/74 family which is fully compatible with DTL and TTL. It is specifically designed for applications requiring very low power dissipation.
PART TWO : WHO USES IT
The military's been using low power TTL for four years, but it's also catching on in portable equipment, data terminals and other industrial applications as well.
PART THREE : ADVANTAGES
Low power TTL offers several nice advantages over standard TTL logic.
First, even at frequencies of 12MHz the devices dissipate very low power and generate less heat on the chip. As a result, low power TTL has proven to be much more reliable than standard TTL. {If you don't believe us, ask NASA.)
Then there's power savings. Typically, low power TTL gives you a factor of JO -power savings over standard TTL. Which means you can use a 2.5A power supply, for example, instead of a 25A supply. Which means you save money.
Speaking of saving money, perhaps the biggest single advantage to using low power TTL is the money you save in your overall systems costs.
For example, low power TTL eliminates the need for a fan. Which eliminates the need for a thermostat. Which eliminates the need for a filter. And so on and so forth. (In fact, one of our customers says that the fan alone costs them enough money that even if they had to pay 2003 more for low power devices in their systems, their overall systems costs would still be less expensive!)
PART FOUR: PRODUCTS
Right now, we have 21 off-the-shelf low power TTL devices (including four MSI functions) : DM54LOO/ DM74LOO Quad 2-lnput NAND
Gate

DM54L01/ DM74L01 Quad 2-lnput NAND Gate, Open Collector
DM54L02/ DM74L02 Quad 2-lnput NOR Gate
DM54L03/ DM74L03 Quad 2-Input NAND Gate, Open Collector
DM54L04/ DM74L04 Hex Inverter DM54L10/ DM74L10 Triple 3-Input NAND
Gate DM54L20/ DM74L20 Dual 4-Input NAND
Gate DM54L30/ DM74L30 Eight-Input NAND
Gate DM54L51/ DM74L51 Dual 2-Wide AND-OR-
INVERT Gate DM54L54/ DM74L54 Four-Wide 3-2-2-3-
Input AND-ORINVERT Gate DM54L55/ DM74L55 Two-Wide 4-Input AND-OR-INVERT Gate DM54L71/DM74L71 R-S Flip Flop DM54L72/ DM74L72 ]-K Flip Flop DM54L73/ DM74L73 Dual J-K Flip Flop DM54L74/ DM74L74 Dual D Flip Flop DM54L78/ DM74L78 Dual J-K Flip Flop DM54L86/ DM74L86 Quad EXCLUSIVE-OR Gate DM54L90/ DM74L90 Decade Counter DM54L93/ DM74L93 Binary Counter DM54L95/ DM74L95 Four-Bit Right Shift Left Shift Shift Register DM76L70/ DM86L70 Eight-Bit Serial-In Parallel-Out Shift Register (NOTE: All devices are available in cavity-dip, molded-dip q!1d flat-pack configurations. We also pl .n to announce some Tri-State*
Ms11ow porr devices. This ends our cram course. If you'd like to learn more, e'll be happy to send you a free copy of our ~ ll course -the liberally-diagrammed, specifitations-packed, 36-page National Low Power TTL Brochure. Plus any of our Tri-State or 54/74 product data.
For yours, write, phone, TWX or cable us today. National Semiconductor Corporation, 2900 Semiconductor Drive, Santa Clara, California 95051. Phone (408) 732-5000. TWX (9 10) 339-9240. Cable: NATSEMICON.
*Tri-State is a Trademark of National Semiconductor Corporation
NATIONAL

THE ELECTRONIC ENGINEER · June 1971

Circle Reader Service #44

81

D/A CONVERTER
..;;;;;::::-.._
Model DAC- IOD is for CRT graphic display applications where it will translate computer commands into deflection signals for writing the graphics CRT presentations. Analog Devices, Pastoriza Div ., 221 Fifth St., Cambridge, Mass. 02142.
Circle Reader Service #125
MEMORY SYSTEM
SEMS 8 (Severe Environment Memory System applications) is a non-volatile, ORO ferrite core system organized in a 3-wire, 3D setup. Access time of 450 ns and cycle time of 1.2 µs. Electronic Memories, 12621 Chadron Ave ., Hawthorne, Calif. 90250.
Circle Reader Service #126
DIGITAL DATA SYSTEM
The 7100 system for industrial data logging and alarm sca nning handles IOOO channels of low and high-level process signals. Westronics, Inc. , 2605 McCart St., Ft. Worth , Tex . 76110.
Circle Reader Service #127
1500 LPM CHAIN PRINTER
The LP 3500 attains speeds from 1240 to 1500 lpm using 48 characters and 132 columns. Potter Instrument Co ., Inc ., 532 Broad Hollow Rd ., Melville. N.Y . 11746.
Circle Reader Service #128
DISK DRIVE
The Mod 321 memory drive unit ts for use with minicomputers . It holds one std. I BM 2315 removable disk cartridge or equivalent. Each cartridge provides 12 million bits of memory at a recording densit y of 1100 bpi . Unicomp, Inc ., 18219 Parthenia St., Northridge, Calif. 91324. (213) 886-7722.
Circle Reader Service #129
82

KEYBOARD
MK-37 / 2040 teletypewriter-configuration keyboard is designed for high-speed data transmission and has additional function keys for use in a CRT displ<'.y terminal. Features include the full, 128 AS CII codes, 12 additional function keys , two-key rollover and error and data lockout. Data Electronics Corp., Burlington, Mass. 01803.
Circle Reader Service #130
CORE MEMORY STACK
Designed for use in the small memories of desk calculators and other compact data processing equipment, this memory stack costs only 2.5 cents/ bit in production quantities. Ampex Corp. , 9937 W . Jefferson Bldg., Culver City, Calif. 90230. (213) 836-5000.
Circle Reader Service #131

THERMAL PRINT HEAD

·sF: L~~ :TE ;· 1_0~·f:: c· ;·;; ~;~~~: · ~~ ;~ ~ J ~·o~

.F-·LH'r'TE ... 1-r i;.·~· T'"-""C PLH'r'T E·· !_IJF'P rii·=PLt

, 194 , ·1WT D

·

'TEI- (OFF' rr·~FLH'

YT D .1
q' TE:t<

E> c c~

I< CO RI.__-.!'~~~~~~

COF'P

YTEt<; CCJPJD $)

CO f'-P D I S PLA~' TD COPP ii !~.

-'2 0 D I S PLAYTE~ C OPP D ! S PL

P P TITC: PI A VTS:- i< 1- 1""1 CP ..... . - -. - · .

The DC-1157 is especially appro-

priate for the new low cost electronic

calculators and for computer and tele-

communication terminals, electric type-

writers and strip printers. Displaytek

Corp ., 1103 Expressway Tower, Dallas,

Tex . 75206. (214) 369-8226.

Circle Reader Service #132

COMMUNICATIONS TERMINAL

..

J-
..:::iillfll"'
--

-~-

--- --=----------.:..-::..

The 4100 is an on-line cassette loaded magnetic tape terminal, plug compatible with Teletypewriter, keyboardprinter and CRT display terminals . It is also for stand alone operation. Techtran Industries, Inc. , 580 Jefferson Rd ., Rochester, N.Y. 14623. (716) 271-7953.
Circle Reader Service #135
TAPE EDITOR
This tape editor (8-channel ASCII) has both off-line and on-line applications . It provides five levels of editing and transmission control : character, word, line, block and record. Special Systems, Inc., 10419 Fawcett St. , Kensington, Md. 20795.
Circle Reader Service #136
SERIAL IMPACT PRINTER
Model 100 is for use as a component of a data terminal , communications printer , remote batch processor , 1. o printer for minicomputers or automatic text editing typewriter. I/ O Devices, Inc. 9 Skyline Dr. , Montville, N.J. 07045.
Circle Reader Service #137
MINICOMPUTER

MULTIPLYING DAC The MP1012 DACPACT~ a 0.015 %
accuracy 12-bit multiplying o / A converter, is for any use where the analog output must be a digitally-scaled replica of th'e reference input. It . may also be used as a normal o / A converter. Analogic Corp., Audubon Rd., Wakefield, Mass. 01880.
Circle Reader Service #133
TICKET PRINTER
Available in either rack-mount or portable instrument case, the Model 2014C accepts BCD information for as many as 10 columns simultaneously. It is for applications that require printing on IBM-size tickets. Digitron Corp ., 2544 W . Main St., Norristown , Pa. 19401. (215) 277-5800.
Circle Reader Service #134

Micro 1600 is a microprogrammable minicomputer which stores logic in an IC co ntrol memory . Microdata Corp ., 644 E. Young St., Santa Ana, Calif. 92705.
Circle Reader Service #138
ASCII CODE GENERATOR
This unit generates all 128 characters of the 7-bit ASCII Code. It is wired for positive logic with a bounce-free TTLcompatible output. $98.00. Mechanical Enterprises Inc ., 5249 Duke St. , Alexandria, Ya. 22304. (703) 751-3030.
Circle Reader Service #139

THE ELECTRONIC ENGINEER · June 1971

SS KEYBOARD
\
I
Heart of the FS-300 keyboard is a Fero-SnapTM ferrite key switch. Using only one moving part, each key switch opens and closes a magnetic path, generating code at the key by transformer action . Fort Electronic Prod ucts, 133 Brimbal Ave ., Beverly , Mass. 01915 .
Circle Reader Service #340
MINICOMPUTE R The EPl-118 minicomputer has a 900
ns cycle time and is expandable from 4 k to 32 k, 18-bit words . With selected peripheral interfaces, the basic 4 k system sells for $5 ,900.00. Electronic Processors, Inc., 5050 S. Federal Blvd., Englewood, Colo. 80110.
Circle Reader Service #341

<> 0

" D l=ii

~

()

0 0

0

¢ "

N EW SIZES N EW PRICES IN CHIP CAPACITORS!

Announcing t he 1971 line of Ceramolithic " chip capacitors from USCC / CE NTR ALAB! Capaci tance ranges - l.OpF to .47Mfd in 50 , 100 and 200 VDC ratings in sizes from .050" x .050" x .040" . Lowest industry prices. New faster delivery- most catalog sizes now avail able off the shelf. Your choice of NPO or W dielectrics which meet or exceed the applicable portions of MIL -C-11015 and MIL-C -39014 . The exclusive Ceramolithic " construction and 100% testing ensures highest rel iability.
For free copies of new 1971 Catalog and Applications Manual , write USCC!CENTRALAB , 2151 N . Lincoln St. , Burbank , Calif. 91504, (213) 843-4222 - or circle information retrieval numb er below.

U. S. CAPACITOR CORPORATION

~--~
CENTRALAB El ectron ic s 01111s1on · GLO BE· UNION IN C

Circle Reader S ervice #47
·t

If you need
TIME CODE EQUIPMENT

look to Chrono- log
for

circuit Time Code Generators. Time Code Readers and A utomatic Tape Search Con-

Make your own
R_eh.a_onbt;{h);~-fS-,LI Ec EV I N~ GS

1 ~ ~

r111:1-m·'' CORPORATION

·

'

Circle Reader Service #45

THE ELECTRONIC ENGINEER · June 1971

83

LID /N51RJMENU

RF POWER METER
Model 42AD Digital Microwattmeter is a MF to K band (200 kHz to 12.4 GHz) power meter. The 3 1/2 digit readout has a free-running display period of 250 ms , but it may be triggered as fast as every I0 ms for system s use where only BCD outouts are required . $1, I00.00. Boon ton Electronics Corp., Pa rsippan y, N.J . 07054.
Circle Reader Service #342

WATTMETER CAL SYSTEM This system uses standard instru-
mentation and a new wattmeter calibrator module (designed Model 5058), to calibrate four terminal wattmeters, ranging in sensitivity from 0.05 W to 14,000 W at freqs. of 50, 60, 400 and I000 Hz. The system is designed such that you can vary the power factor from unity to zero (phase angle 0° to 90°), for co mplete wattmeter calibrations. RFL Industries, Inc., Boonton , N.J. 07005 .
Circle Reader Service #344
POCKET DVM

MOS MEMORY EXERCISER
The MD I00 uses "personality cards" with test sequences specificall y designed for the system under test. The exerciser is micro-programmed t o pro vide test sequences at speed s up to 5 MHz . $13,000.00. Macrodata Systems, Test Div ., 20440 Corisco St. , Chatsworth, Calif. 91311.
Circle Reader Service #343

Model 20 gives yo u 3 de vo ltage ranges plus auto polarity and autoranging. The unit measures 7.6 x 1.2 x 3.2 in. a nd weighs I. I lb . The se lf-contained battery provides up to 8 h operat ion . $7 50,00. Kruger Eckels, Inc., Box 681, So . Pasadena , Ca lif. 91030.
Circle Reader Service #345

3-DIGIT VOLTMETER
Model 3860A has five de ranges wit h ac.;c.;urac.;ies of ±0. 1% of the meas ured reading a nd within ±0.05 % of full scale for a 90 day period . A three-pole active filter is combined with dual-slope integration to provide normal mode rejecti o n of 60 dB at or near line frequency . $350.00. Dana Laboratories, Inc., 240 I Campus Dr., Irvine, Calif. 92664.
Circle Reader Service #346
PORTABLE DIGITAL VOM Model 460 has 26 switch selectable
ranges available for a wide variety of testing situations . These include 5 ac and de voltages, 5 ac and de cu rrents and six resistance ranges with accuracy from ±0.1 % of reading, ±I digit. $395.00. Simpson Electric Co., 5200 W. Kinzie St. , Chicago, Ill. 60644.
Circle Reader Service #347

Tel. (617) 222-3726

REPLACEABLE

Subminiature toggles, rockers and paddle handles by C&K. The most complete line. All models and all options UL listed. Best quality. Best price. Best delivery to a ny place in the world. Now there's a switch. Get the catalog (#700) . C&K COMPONENTS, INC. 103 Morse Street, Watertown, Mass. 021 72 TEL : (617) 926-0800 - TWX: 710 327 0460 The great American switch company.
Also supplied : Pushbutton catalog (#800) Rotary Print Switch catalog (#900)
Circle Reader Service #48
84

· ROUND, CONICAL AND FLAT TIPS
· LOW AND UNIFORM RESISTANCE
· GOLD PLATED · LONG LIFE · SPRING-LOADED CONTACTS
DESIGNED TO BE PLUGGED INTO A MATING SOCKET · REPLACEABLE P 0 G 0 S ARE AVAILABLE FOR CENTERLINE SPACING OF .050" UPWARD · SINGLE, BOARD MOUNTED OR COMPLETE ACTUATING SYSTEMS
PYLON COMPANY, INC. - 57 Newcomb St.
ATTLEBORO, MASSACHUSETTS 02703
Circle Reader Service #49
THE ELECTRONIC ENGINEER · June 1971

The fastest, slowest,broadest line ofmodules available.

If you 're interfacing a computer, you want your modules fast, and Digital gives it to you . The M series is at 10 MHz, and the line is complete. More than 100 physically, electrically, and logically compatible modules that can combine into just about any function you could want. The same modules, in fact, that we use in our latest computers.
But if you 're bu ilding a laboratory controller, or a machine controller, or want to replace those relays, you may want the slowest module you can find. And Dig ital gives you that, too. The K-series is designed to operate at 100 KHz, immune from electrical noise, and this line, too, is complete. Better than 70 mutually compatible modules. The same as we use in our industrial controllers.
Plus the hardware. Digital provides cabinets, connectors, plug-in boards, power supplies -

the works. We have handbooks we'd be glad to send you free. One for the M-series. One for the K-series. One fast. One slow. Write.
DIGITAL EQUIPMENT CORPORATION. Maynard. Massach usetts, Telephone: (617) 897-5111 I ALABAMA. Hunlsville I CALIFORNIA. Anaheim, Los Angeles, and Palo Allo I COLORADO. Denver I CONNECTICUT. New Haven I DISTRICT OF COLUMBIA. Washington (College Park, Md.) I FLORIDA. Cocoa I GEORGIA, Atlanta I ILLINOIS. Chicago I MASSACHUSETTS. Cambridge and Maynard I MICHIGAN, Ann Arbor I MINNESOTA. Minneapolis I MISSOURI, St. Louis I NEW JERSEY. Parsippany and Princeton I NEW MEXICO, Albuquerque I NEW YORK. Centereach (L.I.) , New York City. and Rochester I NORTH CAROLINA. Chapel Hill I OHIO. Cleveland and Dayton I PENNSYLVANIA. Philadelphia and Pittsburgh I TENNESSEE. Knoxville I TEXAS, Dallas and Houston I UTAH. Salt Lake City I WASHINGTON, Seattle I AUSTRALIA. Brisbane. Melbourne. Perth, and Sydney I CANADA, Edmonton, Alberta ; Carleton Place, Ottawa; Toronto. Ontario; and Montreal. Quebec I ENGLAND, London, Manchester. and Reading I FRANCE. Paris I GERMANY. Colog ne and Munich I HOLLAND. The Hague I ITALY, Milan I JAPAN. Tokyo I SWEDEN. Stockholm I SWITZERLAND, Geneva.

Circle Reader Service #51

MODULES· COMPUTE~S

Mlo=D/\CRLD

ICs FOR MODEMS These two ne w circuits a re the SN75 l 50, a dual line driver

··- a nd the SN75 l 54, a qu ad line receiver. Both meet EIA RS-

232C spec ificati o ns. The S N 75 154 receiver includes a dual
po wer suppl y. This lets you ope rate it from a + 12 V supply, no rm a ll y used fo r telephone lines or from a + 5 V supply used

with TTUDTL syste ms. Out puts for the SN75 l 50 driver are

current-limited fo r short-circuit protection to ±25 V. Output

vo ltage levels a re no m inall y ±6 V and the outputs will drive

ca pac itive loads < 2500 pF. Texas Instruments Incorporated,

I nquiry Answe ring Service, Box 5012, M / S 308, Dallas, Tex .

75222.

Circle Reader Service #355

LI NE DRIVER/ RECEI V ER SE RI ES
T he Q C 7820/8820 a nd QC 7830/8830 devices operate on a s ingle 5 V powe r suppl y and are guaranteed to operate over th e full milita ry te mp. range. The QC 7830/8830 driver perfo r ms the du a l fo ur in put NAND and ANO function. The outputs are ba la nced and designed to drive line pairs with impeda nces of 50 I! to 500 I!, or single-ended lines . The QC 7820/ 8820 receiver has two separate receivers on one silicon chip. Th e inputs ca n be co nn ec ted to coaxial or twisted pair lines, a nd th ey acce pt sma ll di ffe rential signals, while rejecting la rge co mm on mode ones. Q ua lidy ne Corp., 3699 Tahoe Way ,
Sa nt a C lara, Calif. 95051. Circle Reader S ervice #3 56

M OS SHI FT REGISTER

....
T he M K I007 P is a quad, 80-bit MOS dynamic shift register tha t pro vides full TTL/DTL compatibility at all inputs and o utputs, includi ng th e single-phase clock. You will find it useful in lin e memo ries of CRT display devices and in the buffer mem o ry units of pu nched card readers. Features include a cloc k fr eq uency ra nge of I0 kHz to 2.5 MHz and recirculate logic o n th e chip a t eac h of the four inputs. $13.50 ea. in qu a n. of 100 or more. Mostek Corp., 1400 Upfield Dr .. Ca rro ll ton, Tex. 75006. (214) 242-1494 .
Circle Reader Service #357
86

NEW MOS PROCESS This new manufacturing process is know as RMOS (Ref-
ractory Metal Oxide Semiconductor). It uses molybden um as the gate metal and because moly can withstand in excess of 1100°C without melting, it can be applied before diffusio n is performed . This results in self-alignment between the gate a nd diffused region and thus provides minimum gate-to-source and gate-to-drain capacitance. The first products to be offered are the GER 1507 and the GER 2507 , dual IOO-bit dynamic shift registers and the GER 1101 , which is a 256-bit memory array. GE Integrated Circuits Dept. . Electronics Park, Syracuse, N.Y. Circle R eader Service #358
BEAM LEAD OP AMPS

The RC74 I BL and RM74 I BL are commercial and military

versions of a high gain, internally compensated operational

amplifiers. Because of the advantages of one-step bonding of

gold plated beam leads , these nitride passivated pretestable

chips are particularly suited for hybrid applications. Ray-

theon Semiconductor, 350 Ellis St., Mountain View, Calif.

94040.

Circle Reader S ervice #359

FUNCT ION GENERATOR IC

T he 566 is a voltage controlled oscillator that produces two outputs simultaneously: a buffered square wave and a buffe red triangular wave. Frequency of oscillation is determined by an external resistor, a capacitor, and the voltage applied to the control terminal. The oscillator can be programmed over a I0-to- l frequency range by proper selection of the external resistance, and it can be modulated over a I0-to- l range by

the control voltage. $6 .00 ea. (I 00-999 quan.). Signetics

Corp., 811 E. Arques Ave ., Sunnyva le, Calif. 94086. (408)

739-7700.

Circle R eader S ervice #360

DATA ACQUISITION SYSTEM IN A MODULE
The DAS-16 interfaces directly with DEC, Data General, Hewlett Pac kard, Varian and most other minicomputers. The unit con tain s an eight or sixteen channel multiplexer, sample a nd hold amplifier, AD converter, system sequencer (with all necessary control and interface logic) and a so lid-sta te readout which displays the multiplexer address and the A D outp ut value. Because of the random and sequential addressing em ployed , individual channels may be sa mpled at rates consistent with their particular bandwidth . Output coding can be binary or BCD, with word lengths of 8, I0 or 12 bits. Prices start at $990. Varad yne Systems, 1020 Turnpike St. , Canton, M ass. 02021. (61 7) 828-6395.
Circle Reader Service #361

THE ELECTRONIC ENGINEER · June 1971

ElectronicGJ\tlemories gently draws
yourattention to an off-the-shelfplanar stack
so small that it will fit most commonly used printed circuit boards.

We built this one to solve our problems with the mini· computer people-and their problems as well. Yes , it's low cost: competitive with any other low cost planar stack on the market. Yes, it's off-theshelf: we can deliver in volume in sixty days or less.
But the main point is this: the size is so small that you can fit this baby on just about any type of PC board. It's 1/ 2" high x 6" wide x 6 1/2" deep. And in that little package you get 4K x 18 bits of core storage. At a price no semiconductor can match. To the mini-computer designer, this means an immediate core memory source regardless of the system 's physical room for storage area.
The stack will operate at either 700 or 800 nanoseconds, depending on whether you order 18 or 20-mil diameter core. Extended temp cores are standard for operation from 0 to 70° C.

The rather unusual "folded" design give$ you almost fifteen percent decrease in drive line inductance. Winding impedance and uniformity compares favorably to the compact frame designs. Much better than other planars.
Incidentally , we held a contest to find a good name for this stack. It is now called the EM 2220. Just goes to prove that we know more about core than about fancy names.
Here and Now: EM 2220 is in limited production for off-the-shelf delivery. Come in and we'll show them to you. Figure about sixty days for volume orders.
em Electronic Memories is
a division of Electronic Memories & Magnetics Corporation, 12621 Chadron Avenue, Hawthorne:.:,..~~77"~ California 90250, (213) 644-9881.

("I still think a couple of 'incredibles' would help." )

THE ELECT RONI C ENGINEER · June 1971

Circle Reader Service #50

87

Take a solid tantalum capacitor out of the military specs and you notice one thing immediately.
Hardly any loss in reliability. And a big drop in price. When you figure y u can get KEMET®E Series dipped solid tantalums for about what yo d pay for aluminum electrolytics, you can start to see all sorts of proble . disappear. Rejects dwindl Shelf life le gthens. Operational life soars. KEMET E Seri tantalums me in four case sizes from 0.175" dian1eter to 0.400" th plug in le son either .125" or .250" precision centers. 0.1to330 up to 50 volt Off the shelf delivery on standard values. Talk to yo Union Carbi Sales Representative about them.Or write us at Unio arbide, Co onents Department, Box 5928, Greenville,Sou Carolina 296 .Telephone: (803) 963-7421.

Circle Reader Service #52

·

COMPONENTS DEPARTMENT

LITER/\TURE

Guide to ROM systems This 22-page brochure includes a
brief introduction to ROMS and a discussion of three of the most common applications: data tables, microprogramming, and character generation. You will also find the theory of

ADD·'% {

READ -ONLY MEMORY

READ CYCLE INITI ATE
COMMAND
operation behind the company's braid transformer read-only memories, and a listing of standard products available. Memory Technology , 83 Boston Post Rd ., Sudbury, Mass. 01776 .
Circle Reader Service #374

Capacitors and resistors Short form catalog EPD DSF-1 in-
cludes performance specs for several new capacitors and resistors. Performance characteristics, physical desc riptions, and military designations for the glass and glass-ceramic capacitors and glass tin-oxide film resistors are provided . Corning Electronics, Corning, N .Y. 14830.
Circle Reader Service #375

Oscillators Cove rin g new products in the fre-
quency control field, this 82-page catalog gives yo u information on such items as vo ltage-controlled oscillators and temperature-compensated oscillators in low profile miniature sizes. It's divided into sections by product, and each is preceded by a discussion of engineering design limits and suggested applications. Performance characteristics, specs, and prices a re providetl as well. Greenray Industries In c. , 840 W . Church Rd ., Mechanicsburg, Pa . 17055.
Circle Reader Service #376

Regulated power supplies manual A comprehensive 37-page catalog has
been organized to provide the reader with a convenient power supply reference manual. Operating specs , selecti on tips and design parameters are included in the literature, as are schematics and a handy color-coded index to facilitate selecti on. Power/ Mate Corp., 514 S . Ri ver St., Hackensack, N.J . 07601.
Circle Reader Service #377

Low power TTL The 54L/74L family is the subject of
this 36-page catalog describing the complete line of low power TTL 1cs. The devices described include NANO, NOR gates, AND-OR in vert gates, flip-flop s, EXCLUSIVE-OR gates, shift registers, and low power 883. Absolute maxi mum ratings, guaranteed operating conditions, test circuits, co nn ection diagrams, and physical dimensions are given for each product. National Semiconductor Corp., 2900 Semiconductor Dr. , Santa Clara, Calif. 9505 1.
Circle Reader Service #378
Optical communications links An inn ovation in the transmission of
digital and analog information, these OCLS are easily installed an d eliminate cable run s, microwave transmitters, a nd the need for FCC licenses. Three models are discu ssed in thi s 4-page brochure: low a nd high speed digital units, for computer/ remote terminal link s and digitized multiplexed a udio links, and an analog version for such applications as vide o tran smission. Un iversity In st ruments Corp. , 5541 Central Ave. , Boulder, Colo. 8030 1.
Circle Reader Service #379
Dice and wafers This interesting and well-illustrated
16-page catalog describes the manufacturer's complete line of semico nductor dice and wafers by device type number . It covers J FETS of a ll so rt s, MOSFETS, dual tran sistors, and flip-chip circuits. There is also a dice index and cross-reference g uid e that li sts the manufacturer's nearest replacement die for any given type number. lntersi l In c., 10900 N. Tant a u Ave ., C upertino, Ca lif. 95014.
Circle Reader Service #380
700 Standard statistical program This is the instru ction manual that
teaches you how to so lve statistical problems with a Wang 700 calculato r. The calculator is loaded with a tape cassette prereco rded with statistical progra ms. Among the important function s in this package are the ca lcul ation of sta nd a rd de viati o n , Ga ussian distribution , corre lati o n fun ctions, c hisq uare distributions, and the error fun ction. Wan g Laboratories In c., 836 North St., Tewksbury, Mass. 0 1876 .
Circle Reader Service #381
Circle Reader Service #53----.+

LITER/\TURE

TEMPERATURE COMPENSATING
SOLDER-INS

for UHF APPLICATIONS

SPECIFICATIONS
CAPACITAN CE: Within tolerance @ 1 MC and 25 °C
CAPACITANC E TOLERANCES: ± 5 % , ±10 % or ± 20% (but not less than ± .25 pf)
WORK ING VOLTAGE: 50 0 VDC
INSULATION RES ISTANCE: Greater than 7500 Megohms @ 500 VDC
FLASH TEST: 1000 VDC for 1 second
ELECTRO DE: Pretinned for assured solderability

These new solder-in capacitors are designed for use in UHF applications requiring the absolute minimum in lead inductance effects. Solder-ins are available in a wide range of temperature coefficients in capacities from 1.5 to 105 pfd.
If your application requires special physical or electrical characteristics, contact RMC's Engineering Department.
Write today on your company letterhead for your copy of the RMC Catalog.

VISIT BOOTH 3Cl2-3C18 IEEE SHOW
RAD I O MATERIALS COMPANY
A DIVISION Of P. R. MALLORY & CO. , INC. GENERAL OFFICE: 4242 W , Bryn Mawr Ave. , Chicago 46, Ill. Two RMC Plan" Devoted Exclu1 ively to Ceramic Capacltort

90

Circle Reader Service #54

Solid state timers The TD-10 series timers, avai la ble as
"time delay on energization" a nd "i nternal" timing functions, a re the subject of a IO-pager. The timers combine cradle relays with solid sta te timing ci rcuits to provide timing from 0.1 to 300
seconds with ± 2% repeat accuracy. In-
cluded in the catalog a re specs, schematics, and mounting dimensio ns. A llied Control Co., Inc ., 100 Relay Rd., Plantsville, Conn. 06479.
Circle Reader Service #396
Function modul es " Function Modules Instru-
mentation ," is described in a 24-pager that covers standard analog function modules for the design of industrial control , monitoring and computational systems. The modules, each of which performs a specific function, fall into five basic groups- input signal conversion, algebraic functions, dynamic response, logic functions, and output signal conversion. Compatible with each other and with other instrumentation, they can also be interfaced with compute rs. Bell & Howell, Control Products Div ., 706 Bostwick Ave. , Bridgeport, Conn . 06605 .
Circle Reader Service #397
Thermal anal ysis system The unique and conventional features
of a low-cost differential thermal analysis system are detai led in a short form brochure. The system 's main feature is its advanced solid-state electronic design which makes it avai lable for $2,850 and hence puts it within reach of research labs., testing and quality control facilities, and teaching progra ms. Yoland Corp. , 31 Centre Ave ., N ew Rochelle, N. Y. I080 I.
Circle Reader Service #398
Standards and publications The following three items are among
the recent new or revised standards and publications now available from the EIA: Reel Packaging of Components with Axial Leads, $1.00; Fixed Film, Dielectric Capacitors in Metallic and non-Metallic Cases for DC Application, $4 .80; and User' s Guidelines for Q uality and Reliability Assurance of LSI Components , $1.20. Write to Electronic Industries Assoc ., 2001 Eye St. , NW, Washington, D.C. 20006.

What DoYou People See In Digitran Switcl1es?

You see what you're switching. Nice big di gi ts. And you can see tremendous space advantages. A typi cal fourunit "MINISWITCH" consumes only 2.76" in length x 1.15" in height. You can't do that with four rotary switches.
Our Thumbwheel sw itches are modularized. It's easy to see that we can supply a switching system with any number of digits yon want without any special toolin g. See also, the ease and versatility of terminating our Thumbwheels. Printed Circuit boards extending out the back can be mated with con nectors or easi ly sold er-wired to plated-thru holes. You can have "wire wrap" terminals or simple wire lea ds. You also can see the possibilities of interconnecting and mountin g J.C. components or discretes on these or modified P / C boards.

Now, about the thin gs you can't see in our switches. You can't see our coding capability, but in our new ca talog, we list dozens of standard codes and have hundred s of others in our files. You can't see the positive and audible "click" between each switching position . You can't see the quality controls that guarantee a million accurate swi tchin g operations. And th e thousands of application problem s we've solved.
So, see for yourself and send for our new complete ca talog. And show us yo ur need for a sa mple and we'll send you one. After all , seeing is believin g.

\ DIGISWITCH® medium sizedsealed or unsealed 8, 10, 12 or 16
MINISWITCH !D miniature-sea led or unsealed 8 or 10 positions

THE DIGITRAN COMPANY I A Divis ion of Becton, Dirki.n «on and Co. I B-D
855 So. Arroyo Pkwy., Pasadena, Calif. 91105 Phone (213) 449-3110 TWX 910-588-3794

THE ELECTRONIC ENGINEER · June 1971

Circle Reader Service #55

91

LITERl\TURE

For quick information use the reader service card inside th e ba c k cover.

MOS ICs Although th e 80 pages of this cata log
a re available as individual spec sheets, their co ll ect io n int o a s ingle so urce makes this book ve ry va luab le . Pattern selection tab les have been added to the information o n ROMS . There are schematics a nd connection di agra ms for
Vee
..
shift registers a nd clock drivers, as well as inp ut and performan ce graphs fo r a na log swit ches. Applications, defi nitio ns of terms, and code conversion tables are amo ng the ext ras yo u' ll fi nd . National Sem ico ndi c tor Co rp ., 29 00 Semico nd ucto r Dr .. Santa C lara, Ca lif. 9505 1.
Circle Reader Service #365
Digital ta pe transports Prod ucts a nd services offered by this
company are outlined fo r yo u in this 12page brochure. If yo u' re loo kin g for di gi tal tape transports, more th a n 300 I BM -compat ibl e m odel s a re offe red . Their characteristic features in cl ude 45 a nd 74 in ./s transports, a 7-in. reel unit , an incremental si ngle capsta n servo, and incremental rates up to I000 steps / s. You have yo ur choice of 7- a nd 9-track operation a nd three reel sizes . Pe riph era l Eq uipment Co rp ., 9600 Irondale Ave ., Chatsworth , Calif. 91311.
Circle Reader Service #366
Digital ICs RCA 's c o s/Mos CD4000A series rcs
feat uring low vo ltage designs (from 3 V to 15 V) are discussed in a handy fo ldout brochu re. The guide covers the new A series , whi c h is unilatera ll y interchangeable with th e currentl y ava il a ble C D4000 seri es , a nd, in addition, makes possible designs req uiri ng rc s that operate at low suppl y vo ltages with good electrical performance, high reliability, and simp lified ci rc uitr y. R CA / Commercial Engineering , H arriso n, N .J . 07029 .
Circle Reader S ervice #367
92

MSI handbook For di gi tal sys tem s desi gners thi s
handbook is a must. The I00-page book pro vides s pecs, descriptions, and typical applications of MS! 1c s. Vol. 2 of the Designer's Choice Logic handbooks, this book covers shift a nd buffer registers, gati ng steerin g and decodin g a rrays , a n.d decoder / dr ive r displ ays, a mo ng others. As with Vol. I, this edition is full y supplemented with schematics and diagrams, and graph s illustrating specia l characteristics. Signetics Corp ., 8 11 E. Arques Ave., Sunnyvale, Calif. 94086.
Circle Reader Service #368
De power suppl y guide You can find the most suitable power
suppl y for yo ur requirements by using thi s 36-page de power suppl y se lection g uid e . Wheth er yo ur app li cation requires co nsta nt voltage powe r supplies, a co nstant cu rren t output , or a crossover bet ween co nstan t vo ltage and con-
~..:-...:.-

Micro 400 reference ma nu al Fi rst of all , the Micro 400 is a general
purpose minicompute r with a starting price of $3 ,250 . This incl udes a I K x 8 co re memory, front panel, enclosure, a nd power suppl y. This reference manual, 75 pages long, co nta in s a ll the necessa ry genera l informati o n as well as co mputer references, detail s on preliminary prog ramming , a nd interface information . M icrodata Corp. , 644 E. Yo ung St. , Santa Ana , Calif. 92705.
Circle Reader Service #3 71
Electronic calcul a tor Here is a so lid -state electronic unit fea-
turing a 14-dig it reado ut an d reca ll a ble memory. In thi s sho rt brochure, yo u' ll fine a summ ary of feature s which expl ains th e decim al-comma system , memory , mec han ica l fea tures, ca pacity, and func ti o ns. As fo r capabiliti es, it perfo rm s the fo ur basic functions as well as multipl ying an d di viding by a constant , acc umulatio n of products a nd qu otients, and automatic squ a ring and square root extraction . SEACO Co mputer- Di spl ay Inc., 2800 W . Kin gsley Rd ., Garland , Tex . 75040.
Circle Reader Service #372

sta nt c urren t, yo u' ll find th e necessary information o utlined in tables as well as specs which include performance ratings, specia l features, o ptions, and outlin e dr aw in gs . Hewl ett-Pa c kard Co., 160 I Cali fornia Ave., Palo A lto, Ca li f. 94304.
Circle Reader Service #369

Consumer circuits You may be surprised at the size of
Tl 's consumer circuit line . For example, for a co lo r TV sys tem yo u' ll find the following: voltage reg ulators for varactor tuners, rcs for automatic tunin g, so und system amps, video i-f amplifiers, power
Deflection
TV Jungl e

Analog gate selection chart Here's a design aid to help yo u select
an ap propriate gate for a specific analog application. Schematics and characteristics are given for the complete line of JFET analog gates, a nd yo u' re given available package types, te mperat ure g rade s, a nd specify in g information . T eled yne Semico nductor, 1300 Terra Be lla Ave. , M o unt a in View , Calif. 9404 0 .
Circle Reader Service #3 70

supplies, TV j ungles, a nd chrominan ce rcs. And you ' ll find similar selections for such applications as a-m / fm radioph ono system s. Texas Instruments Inc ., Box 50 12, M / S 308, Dalla s , Tex . 75222.
Circle Reader Service #373

THE ELECTRONIC ENGINEER · June 1971

THE ELECTRONIC ENGINEER · June 1971

Your next OUM could cosi too much!
....unless vou have the whole picture
How do we know?
Recently we surveyed a number of aerospace, electronics and industrial firms to see how they were using their
DVM's. Half of the DVM's weren 't being used to their full capacity. $3000
instruments were doing the job that a $1400 instrument could do, and
$1400 instruments were doing the job that could be handled by a $400
instrument. We even found analog instruments being used where digital
instruments could do the job more efficiently.
That prompted us to take a hard look at our product line. Shouldn't there be a DVM for every application from production lines to sophisticated metrology labs?
We started by adding a 3-digit DVM . . . ideal for use in the simplest of
applications. We introduced two new 4-digit instruments to cover systems
and bench use, then capped it off with two 5-digit instruments for the
more critical applications where that extra digit is mandatory.
A complete line of associated hardware and plug-ins was
developed for millivolt, AC voltage, and megohm measurements , plus BCD and programming for systems work. For the time being , the job's
done ... the industry's most complete line of DVM's ... 3-, 4and 5-digit instruments from $350
to $6500 . .. to fit every budget ... for eve ry conceivable application.
Which one suits yo u best? Write for our new brochure , or better still , ask for a demonstration and get the whole picture!
Of course, we' re still making the 5700 ... the standard of the
industry .. . the DVM that 's good enough to calibrate other DVM 's.
®
l~ / F=l/r-1/F=l l
Digital Voltmeters When test and measurement count
Dana Laboratories, Incorporated 2401 Campus Drive
Irvine, California 92664 (714) 833-1234
93

Advertisers-June 1971
No li abil ity is assume d for err or s or omissions. This Index is publ ished for a convenience.

THE ELECTRONIC
ENGINEER

ACOPIAN CORP.. .. ................. ..... .......... .. .. ............... .... IFC

Mort Barish Associates . Inc.

AEROVOX CORP.................................... ... ...... ............. 7

Lescarboura Advertising. Inc.

ALLEN· BRADLE Y CO... ...... .... ......

...... ...... .. 19

Hoffman-York. Inc.

AMF INC., POTTER & BRUMFIELD DIV........................ 95

Fuller & Smith & Ross. Inc.

AMP, INC.. .... .... ........................................ ..... ... ...... .. ... . 27

Aitkin- Kynett Co ., Inc .

ANALOG DEVICES, INC.......... .. ... .... .. ..... .. ... .... ...... .... .. 40

Kalb & Schneider. Inc.

BUSSMANN MFG. DIV.... .. ............................ .... ........ ... 74 Henderson Advert1s1ng Co .

CEA, DIV. OF BERKLEONICS, INC................................ 15

Jansson Adv. ·Inc .

CENTRALAB SEMICONDUCTOR ................................. 79

Gordon & Baldwin Adv.

CITIES SERVICE CO., CHESTER CABLE

OPERATIONS ........... .............

......20, 21

Lewis Advertising

CHRONO·LOG CORP... ... .. ...... ... ................................... 83

Mo rt Barish Associates. Inc.

C & K COMPONENTS, INC......................

84

Van Christo Assoc iates . Inc .

COMPUTER LABS ......... .......... ...... ... ...... ...

77

John Talbot & Asso ciates

CUSTOM ELECTRONICS .... ... .. ...

18

Laux Advertising. In c.

DANA LABORATORIE S...... ... ... .... ................................ 93 Rose Associates
DATAPAC, INC. ....... ...... .... ........ ........... . ............. ....... ... 26 Enyart & Rose
DIGITAL EQUIPMENT CORP....... ... .... ... .................. 38 , 39 Creamer. Trowbr idge . Case & Basford . Inc .
DIGITAL EQUIPMENT CORP......... ... ......... .... ............ .. 85 Kalb & Schneider. Inc.
DIGITRAN CO. .................... .. ... ...... ...... ... .... .... ..... ...... 91 Jansson Advertising. Inc.

EDMUND SCIENTIFIC CO...........

... ..... ... .. ...... 96

Walter S. Chittick Co .. Inc .

ELCO CORPORATION................................... .. ... .... ...... 28

Mort Barish Associates . Inc.

ELECTRONIC AS SOCIATES, INC ... ............

89

MS D Adv .

ELECTRONIC MEMORI ES ...........

87

Gumpertz. Bentley & Do lan

FAIRCHILD SEMICONDUCTOR .. ................... Carson / Roberts/ Inc.
FERROXCUBE CORP . .. ... ...... .... ..................... Ferroxcube Marketing Serv1ees Group

.......8 , 9 40

GERMAN AMERICAN CHA MBER OF COMMERCE ...... 96 WOrlen

HEINEMANN ELECT RIC COMPANY ........

5

Thomas R. Sundhe1m Inc .

HEWLETT· PACKARD .... .... ... .

................. ..66 , 67

Lennen & Newell/ Pac ific

INTERSTATE ELECTR ONICS CORP....... .

45

Leland Oliver Co .. Jnc.

ITT CANNON . ........................................

31

Mac Manus . John & Adam s. In c.

JENSEN TOOLS & ALLOYS/ TELVAC INSTRUMENT CO..........
Sheld on W. Gates
94

........... .. 15

KEPCO, INC ..... .. ............................................................ 4 Weiss Advertising
KROHN·HITE CORP...... . ..... .................. ....... .... ...... .... .. 43 Ingalls Associates. Inc .
MACRODATA CO..................................... ............. .... .... 71 Alden Adv. of Ca li f.. Inc.
MALLOR Y CAPACITOR CO......... ...... ....... ............... .. .... 47 Aitkin-Kyne tt Co .. Inc.
MONITOR SYSTEMS, AN AYDIN CO...... ..... ......... ...... .. 14 Ridgaway Philips Co.
MONOLITHIC MEMORIES ............................................ 32 Regis Mc Kenna. Inc .
MOTOROLA SEMICONDUCTOR PRDTS., INC ...... .36 , 37 E. 8 . Lane & Associates . Inc .

NATIONAL SEMICONDUCTOR ........... .... .... ........ ... ...... 81 Chiat/Day. Inc.

PHILCO FORD CORP., Sierra El ec tron ic Operation .. ........................ ....... ........ ........................ . 16
POTTER & BRUMFIELD DIV., AMF , INC .... .. ................ 101 Fuller & Smith & Ross . Inc.
POWERTEC, INC........... ................................... ............. 68
C G A Associates PYLON COMPANY ........ ... .... ......... .... ... ........................ 84
Ame rican Line-A-Graph Corp .

QUADRI CORP.... . M B Advertising

.................................... 73

RCA ........... ... ............... ..... ... ... .... .. ........ .. ................. BC . 23 Al Paul Lefton Co .. Inc .
RADIO MATERIALS CO................................. .......... ... .. 90 M. M. Fisher Assoc .. Inc.
RA YTHEON SEMICONDUCTOR ......... ...... .............. ...... 2 Durel Advert ising

SEMICONDUCTOR ELECTRONIC

MEMORIES , INC... .... ............. .. .... ... .......59, 61 , 63, 65

Gu mper tz. Bentley & Dolan

SPRAGUE ELECTRIC CO.....

...... ....... .... ....... .. .... .. 1

The Harr y P. Bridge Co.

STANDARD MEMORIES, INC ..... ....... ........... ........ ..... .. . 22

M B Advertising

DISTRICT SALES MANAGERS
EDWA RD G. SHAUD BALA·CYNWYD, (Pa.) 19004
One Decker Square (Area Code 215) SHerwood 8-2000
JOSEPH DRUCKER BRYCE GRAY , JR . NEW YO RK 10017 - 100 East 42nd St. (Area Code 2 121OXford7 -3400
JOHN W. BERNHARDT CHICAGO 60606-120 S. Ri verside
Plaza (Area Code 312) 782-1400
G. T. ALFANO NEEDHAM HEIGHTS, MASS. 02194-
570 Hillside Ave. (Area Code 617) 44 4-0010
TERRENCE D. BUCKLEY T HOMAS R. BORIS
LOS ANGE LE S 90005- 3727 W. Sixth St. # 202
(Area Code 213) DU nkirk 7-1271
RAL PH PETERSEN LOS ALTOS (San Fran cisco) 94022
199 First St., Room 335 (Area Code 415) 941 ·6655
RICHARD DUTE CL EVELAND 44114-601 Rockwell Ave .
(Area Code 216) SUperior 1·2860
NEWTON B. COLLINSON ATLANTA 30309-1776 Peachtree St.
N.W. IArea Code 404 ) 872-4723
MICHAEL D. CORLEY DALLAS 75206-Meadows Bldg.
Expressway at Milton (Area Code 214) EMerson 3-6426
HAROLD E. MOTT R. DEN T SHILLINGLAW
Houston 77027 4151 Southwest Freeway
Suite 735 (Area Code 713) 621 -7550

INTERNATIONAL BUSINESS OFFICES

L ondon, S. W. 1 .

. .. Max F. Holsinger

67·68 Jermyn St , St. James·s Dir. European Sales

TRA 6318·9

Roy V. C. Hall, A. Berg

Cables

WHIP LONDON S.W. 1

Manchester 22 ................. 0. I. Goulden Haletop, Wy thenshawe Civic Ct:!ntre MEAcury 3293

4 Dusseldorf·Rath . . E. Hille rbrand, R. Schomburg,

Eitelstrasse 32

W. Heckelmann

Ousseldorr 652031 -32 Cables

WHIP OUSSELDORF

Paris, Se ..... . ... . 70 Rue de Ponthieu Cab les

... S. Brown-Joussard EL Ysees 65- 77
UllP PARIS 16e

Tokyo .... , ...... . ... . . . . . . .C. T. Sakaguchi

Room 814, Togin Bld g., Marunouchi

CPO Box No. 1572

Tel: 211-3506-3509

Cables

CLARENCESAKA TOKYO

TEKTRONIX , INC........... .. ..... ......... .. ..... .... ..,......... ....... IBC

Dawson Inc.

TELVAC INSTRUM ENT CO/ JENSEN TOOLS

& ALLOYS .... .............. ...

15

Sheldon W. Gates

TELEDYNE PHI LBRICK ....

13

lngalis Associates . Inc .

UNION CARBIDE CORP..... ..... .. ....... ... ..... .. .......... .. ....... 88

Ca r gill. Wilson & Acree. Inc .

UNITRODE CORP.............. ................ .................

11

Impact Advertising. Inc.

USCC/ CENTRALAB ...... ...... ........ ..... .....

83

Brown Clark Elkus & Moses. Inc .

USM DYNAPERT DEPT., Industrial

Machin ery Div............ ...........

.................... 17

Klein . Kuria n. Barr & Ross

VARFLEX CORP . ......................................................... . 83 Barlow/ John son . Inc.

BUSINESS STAFF
K. ROBERT BRINK Publisher
BERNARD M. GITTELMAN Advertising Sales Manager
DENN IS J. PER K INS Promotion Manager
LOUI S L. M ARINES Marketing Services Manager
WAR REN OWENS Director of Production
B. A . TATUM Production Assistant WILLIAM HOWAT Circulation Director
JAME S F. NAGY Circulation Manager
JOSEPH P. BABCOCK Reader Service Manager
JOHN H . KO FR ON Chilton Research Services
C. R. WI LHIDE Washing ton Vice -President

T HE ELECTRONI C ENGINEER · June 1971

Copiers, computer peripherals, business machines, precision instruments-you'll find our R10 in a multitude of applications requiring a compact, reliable, multi-pole relay. That's because it probably gives you more design optrons than any other single relay.

Consider these choices: Contact arrangements up to 8PDT. Ratings from dry circu it to 10 amperes. Six styles of contacts, including bifurcated. Sockets with solder or printed circuit terminals including one for mounting the relay horizontal to a printed circuit boardall with or without grounding provisions.

R1~

rcompact,

Mechanical life up to 100 million operations. Electrical life ranges from 100,000 to 100 million operations depending on load and voltage. Coils for DC operation from 3.0V to 115V can be supplied. ACoperated R10 relays to 2 Form C are also available. R1 O relays have Underwriters' Laboratories' Component Recognition, File 4281 O.

multi-purpose relay. The single lot price for a 4PDT, 2 amperes R1 O relay is only $3.60. Quantity discounts apply.

You might say P&B designed it to be manythings to many people.

Order R10 relays from leading electronic parts distributors or call your P&B representative. For a complete, 194-page relay catalog, write Potter & Brumfield Division of AMF Incorporated, Princeton, Indiana 47570. Telephone : (812) 385-5251.

A~F
POTTER & BRUMFIELD

P&B performance.Nothing else comes close.
Circle Reader Service #56

Ca pac itors Thi s ne\~ se rie s of capac it ors offe rs
t he des igne r a range of ca paci tan ces from 2.2 to 330 µ F. with a tolerance of ±20% and a wo rking vo ltage ra nge from 40 to 6.3 Yd c. Operating ambient te mperature ra nge is from - 80° t o I 25 °C. Failure rate is 0.02 % per 1,000 ho urs at rat ed vo ltage a nd 25 °C ambient te mp e rature. Phi lips , Bo x 523. Eindh ove n. The Netherlands.
Circle Reader Service #4 15
O scill a tor and amplifier devices The product information supplied in
this 24-page cata log on Gunn and avalanche diodes and transisto rs is fJily supplemented with descriptive material.1 T he first section , for example, provides data on basic mechanisms and oscillator design . Graphs illustrate electrical and performance characteristics; there's design information accompanied by schematics ; and there are diagrams to illustrate the properties discussed. AE I Semi co nductors Ltd. , C a rholme R d ., Lincoln, England .
Circle Reader Service #4 16

Se mico ndu ctors More th a n 500 pages long, this cata-
log gives yo u deta iled information on ge rmanium a nd silico n tran sistors and di odes. An introdu ctory sec tion provides a summ ary o f types, accesso ry information , nomenclature for semiconductors, mounting and soldering inst ructions, and an explanation of technical data. A very comprehensive catalog, the in fo rmati o n is prese nt ed in both English and German and is offered to yo u by A Ilgemeine Elek tricitats-Gesel Isch aft. A EG-Telefun ken , Fachbereich Halbleiter. Yertrieb. 7 100 He ilbronn , Pos tfa ch 104 2, Germany.
Circle Reader Service #4 17
Plugs and soc kets The plugs a nd soc ket s and cables de-
scr ibed here are for use in medical e lectronic equipment. Dim ens io n al drawings acco mp a ny each ph oto a nd product description. Characteristics are listed in chart form. Perena, Siege Social: 16, Boulevard de Charonne, Pa ri s -XX e. F r a n c e.
Circle Reader Service #4 18

Digital measuring instruments How to select a digita l vo ltmete r or
m ul ti meter a nd a d isc ussion of t he general principles of co nversio n precede the first section of t h is 120-page cata log. T he counte rs-freq uency mete rs a nd panel mete rs sections fo ll ow in for m a ti on d iscuss ions also . Co m p lete prod uct d ata is provided fo r eac h m odel, includ ing description , specs, pac kaging, and explanatory d iagrams an d grap hs. Sch neider Electro nique, 12 Ru e Louis Bertrand, 94- IYR Y, France.
Circle Reader Service #4 19
Osc ill ator mini-st yle Th e co mponents that make up this
osc ill ato r . the crystal and a microelec tr o ni c IC comprised o f tran sistors, resist o rs, and capacitors, are all pac kaged within a T0-5 tran sistor ca n less than 9 mm in diameter and 7 mm h igh. It wil l p rov ide accurate and stable frequency control. operating in a ny freq uency betwee n 10 MH z and 22 MHz. Marconi Communication Systems Ltd., Marco ni H ouse, Chelmsford, Essex , England .
Circle R eader Service #420

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charts, d iagrams, il lustration s. A treasure house of optic:al and scie nt ific equ ipmen t available direct from stock fo r industry, research lab s, design engineers, expe ri menters, hobbyists.
AMERICA' S GREATEST ONE-SOURCE MARKET PLACE Hard-to-get surplus bargains. Ingen ious scientific tools. Thou· sands of <Omponents; lenses, prisms, wedges, mirro'1, mounh, a ccessori es of all descriptions. Hundreds of instrum wnh1 lasers, compa rato rs, magn ifiers, mi croscopes, projtctors, telescopes, binoculars, photo attadrments, bla ck li gh t equ ipmen t and th e largest se lection of un ique ligh ti ng ite ms In t he coun t ry.
ORDER DIRE CT WITH ABSO LUTE CONFIDENCE Edmund ships mo re than 5,000 orders mont hl y to t he coun· try's largest industr ials. Every item completely guaranteed . You must be sa tis fi ed with any pu rcha se or retum it in 30 days fo r your mon ey back. Shop the catalog of America's
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C ircle R eader Ser vice #58

96

October 14- 20, 1971 5th International Congress with Exhibition for Instrumentation and Automation - the international industrial and commercial center for instrumentation and automation - research and development - at the new fa ir grounds.
oosseldorf
Informati on: Ge rman Americ an Chamber of Com me rc e, Inc. 666 5th Ave nue , New Yo rk , N.Y. 10019 (212) 562-naa German American Chamber of Comme rce of Chicag o
n East Mon roe Street, Chicago, I 11. 60603 (312) 782-8557
Circle Reader Service #59
THE ELECTRONIC ENGINEER · June 1971

SAVE GAIN
$$$ performance
over any other 50-M Hz, plug-in oscilloscope.
$2 2 00 5D-MHz OSCif-~~~~~~~.:~~~~d delaying sweep ... . 19 0 0 5-mV dual-trace amplifier and single time base . . . . . . .. . 16 5 0 5-mV single-trace amplifier and single time base . . .. .. .
!i' AND LOOK AT THESE BONUSES: 3 plug-in compartments and mainframe mode switching ~6-1 /2-inch CRT - 50% larger than 8 x 10 cm CRT's
[YJ' time bases have 5 ns/div
sweep rate
~ amplifiers and time bases
accurate within 2%
~ high writing-rate CRT
gives a brighter trace

ROOM TO
GROW
SELECT FROM
22
PLUG-INS

If you wish , select a plug-in for the second vertical compartment to give you 10 µVI div at 1 MHz or 1 mV/div at 55 MHz or 1 mA/div at 55 MHz or another dual-trace unit for 4-trace capability, etc., etc. Plug-in prices start at a low $250. Call your nearby Tektronix field engineer today for a demonstration.
7403N Oscilloscope ........... . . . . ... $950
7A18 Dual-Trace Amplifier, Option 1 .... $500

7A15 Single-Trace Amplifier .......... $250

7853N Dual Time Base ..... . .. . ...... $750

7B50 Time Base . . .. .. . ...... . ....... $450

TEKTRON IX@

U.S. Sales Prices FOB Beaverton , Oregon
Available in U.S. through the Tektronix lease plan.

committed to technical excellence
Circle Reader Service #65

From RCA,the world's leader in power devices··· new power
hybrid circuits for your needs

OP AMPS ANO LINEAR AMPS HC-1000, TA7625A, and TA7926
Up to 7 A peak current
·Servos ·Tape drivers · Stepper motors · Linear motors · Magnetic deflection ·HF amplifiers to 100 kHz

HIGH CURRENT POWER ARRAYS TA7631 and TA7632
IC levels to 300 amperes
·High power inverters · Power supply regulators ·Variable-speed inductance motors · Stepper motors

SERIES REGULATORS TA7955, TA7956, and TA7957
5, 8, and 12 volts
· 4 A current capability · Integral crowbar trigger · Booster capability to 12A

HIGH GAIN CURRENT AMPLIFIER PAIRS TA8141
Dual 5 A Darlingtons
· Hammer drivers · Solenoid drivers · Stepper motors

If your design requires power amp lifi ers, or power con t rol c ircu its, or power supplies or something else you don't see here, ca ll your local RCA Representat ive . For a copy of catalog 2L 1149, along w ith product sheets detai ling des ign concep'ts on various RCA power hybrid circu its, write: RCA , Commercial Engi neerin g, Sect ion 59 F /UC3, Harr ison, N.J. 07029 . International: RCA, Sunbury-o n-Thames, U.K., or P.O. Box 11 2, Hong Kong.
Circle Reader S ervice #66

ncn
Solid State